Prostomium

“ The prostomium very broadly cordate, notched or constricted at the sides near the anterior third which is distally broadly rounded; tentacles inserted on each side at or just distad of the constriction, conical and of moderate length; caudal margin conspicuously angularly incised at middle and there embracing a conspicuous nuchal papilla. Eyes about twice their diameter apart. The type is incomplete caudally, at present consisting of ninety-five somites and having a length [7] of 35 mm. with a maximum width, exclusive of parapodia, of 2 mm. The body at present has a purplish tinge. ”

“ Sabelliformia.—The prostomium is entirely hidden by the forward extension of the peristomium; the tentacles are very small, being frequently represented merely by small knobs of sense-cells; the palps, on the other hand, are greatly developed, branched, and contain blood-vessels, acting as respiratory as well as sensory organs. The peristomium never carries cirri or chaetae, and it is usually raised up into a projecting collar, used in fashioning the lip of the animal's tube. The parapodia are but feebly developed ”

“ The prostomium is very small, but retains a pair of well-developed tentacles; the palps, which are subdivided as in the Sabelliformia, have become fused with the ventral edges of the peristomium, and appear as a series of ridges on each side, carrying numerous filaments. The thorax consists of five segments, the notopodia of three of which are well developed and bear strong chaetae; dorsal cirri are present along the greater part of the body, and act as gills. The arrangement of the chaetae and of the internal organs is as in the Sabelliformia. The worms form tubes of sand. ”

“ Prostomium a little longer than wide, narrowed anteriorly, sides convex; a short lobe, rounded in front and bearing the four tentacles, is set off by a weak constriction from the basal part. Unpaired tentacle situated well caudad, more slender than the paired ones but nearly as long. Eyes not detected. Ventral tentacular cirrus of II of a thick, leaf-shaped form, sublanceolate in outline and much like the notocirri. The other tentacular cirri longer and filiform. ”

“ The prostomium, though narrow, is long, conical, annulated, and carries at its apex four very small tentacles; at its base a pair of palps. Special retractile gills are present. The armed pharynx is very long, and when protruded appears wider than the animal. The members of this family are without any system of blood-vessels, but the coelomic corpuscles are coloured red. Glycera has four jaws, the parapodia are all alike (Fig. 136, C) . G. capitata Oerst. is 2 or 3 inches in length, is yellowish in colour, with a dark-red median line. It may be found burrowing in sand. ”

“ The middle region of the body bears notopodeal fasciæ of long, fine, simple, natatory setae in addition to the compound neuropodials. The appendage of the compound setae differs from that of californiensis in having the accessory tooth farther distad, well beyond the middle of the concave edge, whereas in the other species it is normally rather proximad of the middle. In the present species the prostomium is proportionately larger, less covered by the peristomial flap which does not extend over the base of the median tentacle. The palpi are not fused so far distad, being united only at base ”

“ The setae are implanted metamerically in accordance with the metamerism of the body, which consists of a prostomium followed by a number of segments. The number of segments in an individual is frequently more or less definite. ”

“ The prostomium has five tentacles; there are long peristomial cirri, and in general their anatomy agrees most closely with that of Phyllodocids. Alciope, Asterope, Vanadis, Nauphanta are genera of the family; [378] none have been recorded from the British area.
Fam. 5. Tomopteridae. [379] —This includes but one genus, Tomopteris, which is pelagic. The transparent, colourless body consists of only a few (eighteen to twenty) segments; the parapodia are as long as the body is wide, and carry no chaetae; each is bilobed, and fringed with a membrane ”

“ Setae always present and often very large, much varied in form and very numerous, borne by the dorsal and ventral parapodia (when present) . The prostomium and the segments generally often bear processes sensory and branchial. Eyes often present and comparatively complicated in structure. Clitellum not present as a definite organ, as in Oligochaeta. The anus is mostly terminal, and there are no anterior and posterior suckers. Nervous system often imbedded in the epidermis. Vascular system generally present forming a closed system of tubes. ”

“ Unlike those of alata, somites II and III are not confounded laterally but are distinct throughout. Prostomium short. Tentacles mostly lost in type; rather slender, not long, apparently in but a single transverse series. Peristomium deeply excavated at middle below, the bottom of the excavation rounded and the peristomium produced on each side of this into the usual large lobes. The branchiæ, as in the genotype and other species, strongly asymmetrically developed. The right anterior branchia is much the largest, the trunk very long, with the left anterior much smaller. ”

“ The body consists of a number of exactly similar or closely similar segments, which are never fused and metamorphosed, as in the Arthropoda, to form specialized regions of the body. It is, however, always possible to recognize a head, which consists at least of the peristomial segment with a forward projection of the same, the prostomium. A thorax also is sometimes to be distinguished from an abdomen. Where locomotive appendages (the parapodia of the Polychaeta) exist, they are never jointed, as always in the Arthropoda ”

“ The anterior segments differ from the rest in the absence of gills and in the character of the chaetae (Fig. 133, A, p. 261) .
P. ciliata Jnstn. inhabits soft mud tubes near low water; it also makes U-shaped galleries in stones and shells, and the tube projects from each mouth. The worm is about 1⁄2 inch long, consists of some forty segments, and is yellowish or flesh-coloured. The prostomium resembles that of Spio; the peristomium is raised into a slight collar at each side. The anus is surrounded by an incomplete funnel. ”

“ Spodumene crystallizes in the monoclinic system, the crystals having generally a prismatic habit and being often striated longitudinally. It has perfect prismatic cleavage, and imperfect cleavage parallel to the clinopinacoid, whilst a lamellar structure may be developed by parting along the orthopinacoid. The hardness is 6.5 to 7, and the specific gravity about 3.16. Though generally a dull mineral, some varieties of spodumene are so brightly coloured and transparent as to be valued as gem-stones. ”

“ The specific gravity of osmium in the pulverulent form is about 10; but after having been heated to the fusing point of rhodium in the oxyhydrogen jet, it acquires a density of 21·4, and in the crystalline state it has a sp. gr. of 22·477. Osmium appears to be the least fusible of all the metals.
There are five known oxides of osmium:
1. Osmium protoxide. (OsO) . The anhydrous protoxide is of a greyish-black colour. It is insoluble in acids. Its bluish-black hydrate, which dissolves in hydrochloric acid, forms a solution of osmium dichloride of a deep indigo blue colour. ”

“ Metallic lead tarnishes when heated in the oxidation flame, and is instantly covered with a grey matter, consisting of the protoxide and the metal. It fuses quickly, and is then covered with a yellowish-brown protoxide until all the lead is converted into the protoxide, which melts to a yellow liquid. In the reduction flame and upon charcoal, it is volatilized, while the charcoal becomes covered with a yellow sublimate of oxide. A little distance from the assay, this sublimate appears white (carbonate of lead) . Protoxide of lead melts in the flame of oxidation to a beautiful dark yellow bead. ”

“ Several oxides of osmium are known. The protoxide, OsO, is obtained as a dark grey insoluble powder when osmium sulphite is heated with sodium carbonate in a current of carbon dioxide. The sesquioxide, Os2O3, results on heating osmium with an excess of the tetroxide. The dioxide, OsO2, is formed when potassium osmichloride is heated with sodium carbonate in a current of carbon dioxide, or by electrolysis of a solution of the tetroxide in the presence of alkali. ”

“ If a trace of protoxide of iron remains in the solution another cubic centimeter of nitric acid ought to be added and the boiling continued so long as any reddish-yellow vapors are visible, more hydrochloric acid also being added to keep the solution from being dried up. The process is continued in this way until two tests have given no reaction of protoxide of iron, when the solution is diluted with water; but no dilution should take place until the oxidation is complete, because in the course of it the solution ought to be kept as concentrated as possible. ”

“ The protoxide is blue when precipitated, but it is supposed to contain water, or to be a hydrate; as it is dark grey when heated. The blue oxide in a short time after precipitation being still under water, changes to a yellowish or dead-leaf colour; which also appears to be a hydrate of the protoxide, as it dissolves in acids without giving out gas, and yields the blue oxide by an alkali. ”

“ Persons who handle the compounds of protoxide of iron, should be aware of the fact that few substances are more speedily and completely destroyed than these by the action of {230} moist air; thus, one hundred parts of the carbonate of iron, require less than seven parts of oxygen for complete conversion into sesquioxide of iron, and one hundred parts of pure copperas require less than three parts of the same element to effect a like change in all the protoxide of iron which it contains. ”

“ Phosphorite, when occurring in large deposits, is a mineral of much economic value for conversion into the super phosphate largely used as a fertilizing agent. Many of the impure substances thus utilized are not strictly phosphorite, but pass under such names as “rock-phosphate,” or, when nodular, as “coprolite” (q.v.) , even if not of true coprolitic origin. The ultimate source of these mineral phosphates may be referred in most cases to the apatite widely distributed in crystalline rocks. ”

“ In addition to free phosphoric acid, iron phosphate is separated, which gradually passes into an insoluble form by the abstraction of water due to the crystallization of the gypsum. The alumina present [Pg 141] in a superphosphate seems to have no direct influence on the process of reversion. Its phosphate salt is not acted on by the acid calcium phosphate. Even when a superphosphate solution is treated with alum no precipitation is produced, except on warming, and this disappears when the mass is again cold. ”

“ The texture of this ore is compact: its fracture, conchoidal, surface sometimes dull; colour, iron black or lead gray, often bluish, iridescent, or reddish from a mixture of protoxide. It is easily melted even by the heat of a candle; but more difficult of reduction than protoxide. This ore yields to the knife, assuming a metallic lustre when cut. Its density varies from 4·8 to 5·34. Its composition according to Klaproth is 78·5 copper, 18·5 sulphur, with a little iron and silica. Its equivalent constitution by theory is 80 copper + 20 sulphur = 100 ”

“ Protoxide. The yellow oxide of lead is the only one capable of forming salts with acids. Lavoisier found the oxygen of this oxide combined with 100 lead to be 4.47; Wenzel, 10; Proust, 9; Thomson, 10.5; Bucholz, 8; Berzelius, 7.7. This last accords best with my own experience; but it is chiefly from the other combinations of lead, that the weight of its atom as well as that of the protoxide are determined and confirmed, as lead forms several very definite compounds with acids, &c. The quantity of oxygen in the protoxide may be found by several methods, as under. ”

“ If the hot bead is colourless and remains clear on cooling, we may suspect the presence of antimony, aluminium, zinc, cadmium, lead, calcium and magnesium. When present in sufficient quantity the five last-named give enamel-white beads; lead oxide in excess gives a yellowish bead. If the hot colourless bead becomes enamel-white on cooling even when minute quantities of the substances are employed, we may infer the presence of barium or strontium.
(β) The substance dissolves slowly and in small quantity, and forms a colourless bead which remains so on cooling. ”

“ There are rival inventors, as a matter of course. The French patentees claim the use of cuttle-fish bones, various sea-shells, etc., mixed with pure lime, sulphur, and calcined sea-salt, besides sulphides of calcium, barium, strontium, uranium, magnesium, or aluminium. They also add phosphorus itself, though for what purpose is questionable, seeing that this substance is only luminous during the course of its oxidation or slow combustion, and after this has ended the resultant phosphoric acid is no more luminous than linseed oil or turpentine. ”

“ To obtain the protoxide, mercury must be slowly dissolved in dilute nitric acid without heat, and an excess of mercury must be used. If to 1000 grain measures of nitric acid, 1.2 sp. gr. be put 500 grains of mercury, by occasional agitation the requisite solution will be obtained in 24 hours. A portion of this solution must be treated with a small excess of lime water or caustic alkali, when a black powder will be thrown down, which is the oxide containing a minimum of oxygen, and hence may be considered the protoxide. ”