Scute

“ Femoral scute: Length of border of scute on midline, 24; width of anterior border of scute from midline to inguinal notch, 41; width of posterior border of scute from midline to outer border (along sulcus) , 40; length of outer margin of scute from inguinal notch to femoro-anal sulcus, 46.
Anal scute: Length of margin at midline, 36; length of femoro-anal sulcus, 40.
Remarks.—Noteworthy is the intermediate nature of C. limnodytes when compared with species of the genera Chrysemys and Pseudemys. ”

“ The body is covered more or less with horny scutes or scales, beneath which are several rows of thickened, pitted, bony plates on the dorsal side, and sometimes also on the under side, forming a more or less extensive bony armor. ”

“ The spine of the seventh cervicals is not shielded above by a row of scutes; and the spine of the eighth cervical is only partially covered by the first transverse row of the dorsal series of scutes. The dorsal series is made up of fifteen transverse rows of scutes, each row composed of four or six bony plates. Those containing six plates are the second, the fifth, the eighth, the tenth, eleventh, and twelfth rows, reckoning backward. The fifteenth transverse row of scutes, overlies and covers the spines of the third and fourth lumbar vertebrae. ”

“ The nuchal and dorsal scutes form a continuous shield, but there are two small postoccipital scutes. General colour, dark olive-brown above; the young are paler, with dark markings. The male is remarkable for several peculiarities. The nose is very much swollen, and can be inflated like a bag when the nostrils are closed. In connexion herewith, probably produced by the recoil of the air in the long narial passages towards the choanae or posterior nares, there is a pair of hollow globular swellings, in large specimens of the size of a goose's egg. ”

“ The scutellum is yellow, the abdomen black, with two yellow bands, and a spot of the same colour on each side between the bands. A deep black polished groove extends down the back, from the thorax to the anus, into which the sting turns and is deposited, leaving the anus very circular ”

“ The snout is stout, rather broad; the top of the head is rough but without any ridges. The upper and lower jaw each contain nineteen teeth on either side. The nuchal scutes, six in number, are packed closely together, the four biggest forming a square. Four smaller scutes are arranged in a curved line on the occiput. The dorsal shield is composed of four, sometimes of six rows of larger scutes, of which the central pair is the broadest. The fingers are webbed at the base; the outer toes are broadly webbed, and the outer edge of the hind-limbs is turned into a serrated fringe. ”

“ Adult males of some of the species possess a peculiar armature on each side of the tail, which in females is much less developed or entirely absent. This armature may consist either in simple spines arranged in rows, or in the development of the minute spines of the scales into long stiff bristles, so that the patch on each side of the tail looks like a brush.
C. Ostraciontina.—The integuments of the body form a hard continuous carapace, consisting of hexagonal scutes juxtaposed in mosaic-fashion. A spinous dorsal and ventral fins are absent ”

“ Most of the larger scutes and the upper surface of the bones of the skull have a peculiar gnawed-out, almost honeycombed appearance, as is usual wherever most of the cutis itself is transformed into bone or co-ossifies with underlying bone, while the uppermost layers and the horny layer of the epidermis are much reduced and thinned out. ”

“ Bill short, robust, narrower than the head, regularly conical, acute; upper mandible almost straight in its dorsal outline, as is the lower, both having inflected edges; the gap line nearly straight, a little deflected at the base. Nostrils basal, roundish, open, partially concealed by the feathers. Head rather large, neck shortish, body robust. Legs of moderate length, rather robust; tarsus longer than the middle toe, covered anteriorly with a few longish scutella; toes scutellate above, free, the lateral ones nearly equal; claws slender, arched, compressed, acute, that of the hind toe long. ”

“ The premaxillo-maxillary suture on the palate is not transverse, but extends backwards. In conformity with the length of the snout the maxillaries meet in the dorso-medial line behind the nasal opening, thus excluding the nasals from the latter. The nuchal scutes consist of two large pairs, almost in contact with the dorsals, six of which form the principal longitudinal rows. The gular and ventral scutes ossify in the adult, hence the specific name. The fingers and toes are slightly webbed. General colour above, dark olive-brown; yellowish below. The young are olive with large black spots. ”

“ Plate CCCXXVI. Adult Male, and Young.
Adult with the bill pale bluish-grey, tinged with green towards the base; bare space about the eye, lines on the bill and gular membrane blackish-blue; tarsi, toes, and webs, brownish-black, the scutella light greenish-blue, claws greyish-white; general colour of plumage white; upper part of head and hind neck buff-coloured; primary quills brownish-black, their shafts white toward the base. Young at first covered with very soft white down; when fully fledged, with the bill light greyish-brown, the bare space around the eye pale greyish-blue ”

“ In S. vulgare the males are attached, often several together, to the extreme edges of the two scuta, and therefore immediately over the orifice leading into the sack; in S. rutilum and ornatum, they are attached in concavities on the under side of both scuta, just above the depression for the adductor scutorum muscle. In the former of these species, the pit for the reception of the male is formed by shelly matter not having been deposited over a certain space on the under side of the valve; and the pit is converted by a covering of membrane into a pouch. ”

“ Chromatophores, irregular cells in the mantle which give color to the squid. Exhalent siphon, a funnel or tube opening on the ventral side just below the base of the arms or tentacles. Pen, a remnant of an exoskeleton imbedded in the mantle along the dorsal side. Ink sac, a sac containing a dark, sticky liquid which may be thrown out through the funnel into the water. The opening is near the inner opening of the funnel. Observations. What is the shape of the squid? To what is this shape adapted? Identify the head and the well-developed eyes. How many arms or tentacles are there? ”

“ Scuta.—These valves are important, inasmuch as the animal’s body is attached to them; in Pl. 25, fig. 1, the broken line, surrounding a, b, shows where the body has been cut, in removing the scutum on the near side, the other scutum, S, being left articulated to the tergum, T. In shape the scuta are generally sub-triangular; but in some species of Pyrgoma and in Chelonobia, &c. they are much elongated. ”

“ The glittering insects that darted to and fro on its surface became sea-monsters dire, the gnats that hung above them swelled to albatrosses, and the pond itself stretched out into a vast inland sea, whereon a navy might ride secure, and whence at any moment the hairy scalp of a sea serpent might be seen to emerge. ”

“ The basal portion of the mandibles on each side project, so that if a vertical section of the head through the middle were taken it would be an oval with its greater diameter transverse. The eyes are in strictly triangular patches, with remarkably straight sides. The scuta are so deeply canaliculate along their dorsal centre as to be almost divided into two parts. The dorsum is not perfectly rounded, but there is somewhat of a ridge or angle in the centre. Each scutum is furnished with a regular series of distant large puncta, or perhaps more properly, pores. ”

“ The scuta are ornamented, rarely with a white blotch on each side of the mesial line, but generally with two lateral black dots. The first scutum in the female has the anterior margin oblique as to the main axis of the body, and is prolonged laterally so as to form processes, mostly canaliculate, with a rounded border. In the male the anterior margin is at right angles to the axis of the body, and the lateral parallel to it, so that there are no processes. ”

“ And the timid mollusks, trembling and succulent pulp, have fabricated for their protection the strong shields of their valves,—two concave walls that on opening form their door, and on closing, their house.
A bit of flesh protrudes outside these shells, like a white tongue. In some it takes the form of a sole, and serves as a foot, the mollusk marching with his dwelling upon the back of this unique support. In others it is a swimmer, and the shell, opening and shutting its valves like a propelling mouth, ascends in a straight line to the surface, falling afterwards with the two shields closed. ”

“ It must here be remarked, that as these head-footed mollusks are not "fish," any more than lobsters, crabs, oysters, mussels, &c., which fishmongers call "shell-fish," are "fish," the word "fish" is misleading, and should be abandoned; and secondly, that the names "cuttle" and "squid," as distinctive [Pg 12] appellations, are unsatisfactory. The word "cuttle" is derived from "cuddle," to hug, or embrace—in allusion to the manner in which the animal seizes its prey, and enfolds it in its arms; and "squid" is derived from "squirt," in reference to its habit of squirting water or ink. ”

“ This faculty of reproduction is doubtless designed to enable the creature to escape from its assailants: the detaching of the limb is evidently its own act; and it is observable, that when reproduced, the tail generally exhibits some variation from its previous form, the diverging spines being absent, the new portion covered with small square uniform scales placed in a cross series, and the scuta below being seldom so distinct as in the original member. ”

“ Everyone who has spent a little time in naturalising on the shore, has noticed how often you may find univalve shells, such as those of the whelk and periwinkle, with the top of the shell knocked off. This is nearly always the case with the dead shells that you find strewn along the tide-line; and after a storm, on a rocky coast, you may find shells that still contain the living tenant, in the same sad condition. And you may also meet not infrequently with shells, dead or living, that bear evidence of the owners' efforts to repair them after an accident to the spire. ”

“ You find many with only the backs of their shells sticking out of the mud. This may be the creature’s natural position, but I find far more of them lying quietly on their sides in the shallow water, rocking gently to and fro in the placid undulations as if they were there but to show me their shining colors. But if you watch one intently for a time you will see him open his shell cautiously and put out one foot. ”

“ The animal is like a big black slug, and, in comparison with the size of the slug, the shell is very small. A slug the size of a man's fist would have a shell about an inch long. Most shell-hunters would pass by a Scutum abiguum, not thinking it had a shell embedded in its folds. The shell is found amongst rocks in sheltered places on ocean beaches. ”

“ When surface markings exist on the scuta, they are very useful in defining species. The color is also a good character in some groups. Where one of these fails us the other very generally assists. The form of the last scutum is sometimes distinctive. The best characters, however, are those derived from the genital organs. The form, &c., of the antennæ and head often afford some clue.
Genus POLYDESMUS, Latreille. [24]
Meatus laterales in scutis 5—7—9—10—12—13—15—16—17—18—19—positus. ”

“ Scuta 8. Segments 16. Stomata of the scuta median. Feet and antenna multiarticulate.
In the Cermatiidæ the head is large, more or less truncate anteriorly, having its surface rough and uneven. The eyes are compound and very prominent. The palpi very elongate and spinous. The antennæ very long, and composed of a multitude of joints. The mandibles are elongate and distant. The scuta (eight in number) are rounded and deeply emarginate posteriorly, where they are furnished with a longitudinal, slit-like orifice or stoma. Their surface is more or less roughened with minute tubercles or spines. ”

“ When we threw our nets into the water we caught an abundance of sturgeons, and another kind of fish like our trout, except that the eyes and nose are much smaller, and they have near the nose a bone like a woman's busk, three inches broad and a foot and a half long, the end of which is flat and broad, and when it leaps out of the water the weight of it throws it on its back. ”

“ Colour, when alive, pale, but fine purple; I presume, judging from some dried specimens, sometimes dirty white. The state of the surface varies remarkably: about half the specimens (fig. 1 a) which I have seen, had the outer lamina of shell quite removed, and the surface granulated, owing to the projecting and exposed tips of the upfilled parietal tubes; the radii are not developed, and often even there is no trace of the four sutures; the rather large orifice is somewhat rounded, and the two scuta, with their surfaces disintegrated, have their middle parts deeply indenting the terga. ”

“ Scuta oval, of varying proportions; the basal margin is generally narrow, and blends into the [Pg 101] carina-tergal margin; the internal basal rim generally is well developed, sometimes with, and sometimes without internal teeth beneath the umbones. In P. eburnea, and sometimes in P. crassa, there is a line of apparent fissure, and in P. fissa of actual disseverment, running from the umbo to the apex of each scutum, nearly in the line in which a ridge extends in Lepas: the primordial valves of the scuta in these three species, are seated at the basal angles of the lateral and larger segments. ”