Sir A. E. Shipley

“ On the one hand, therefore, the Tarantula has acquired the habit of striking the wasp in the only point where its blow is instantaneously fatal, while on the other the wasp, with a different object in view, has been led to select the precise spot where its sting will disable without immediately destroying the spider. The latter case is, if anything, the more extraordinary, as the insect can hardly have any recollection of its larval tastes, and yet it stores up for progeny, which it will never see, food which is entirely abhorrent to itself in its imago state. ”

“ At night-time Limulus is apt to leave the sand and progress by a series of short swimming hops, the respiratory appendages giving the necessary impetus, whilst between each two short flights the animal balances itself for a moment on the tip of its tail. ”

“ The Lycosidae, or Wolf-spiders, which chase their prey instead of lying quietly in ambush to ensnare it, are exceedingly interesting in their treatment of their young. The cocoon, or bag of eggs, is carried about on all their expeditions, attached beneath the abdomen, or held by the jaws, and the young spiders, on escaping from it, mount on the mother’s back, and indulge vicariously in the pleasures of the chase from this point of vantage. ”

“ The Epeiridae, spinners of the round web, are certainly, as a rule, very dim-sighted creatures. A fly may be held within an inch of them, but, unless it buzz, it will excite no notice whatever. A careful observation of the performances of the large Garden-spider in securing her prey will soon convince the onlooker that she is guided almost entirely by appeals to her sense of touch communicated along the tremulous lines of her snare. ”

“ Considering the enormous changes that must have taken place in the distribution of land and water even during Tertiary times, it is astonishing that the fresh waters of the world do not contain more species in common with the ocean, but it must be considered that the limited area and comparatively uniform conditions of fresh-water lakes and streams would only permit a limited number of these forms to survive which could most easily adapt themselves to the changed conditions. ”

“ This spider, though strictly an air-breathing animal, spends almost the whole of its existence beneath the water. That it can live in such a medium is due to the fact that the long hairs which clothe its abdomen retain a bubble of air as it swims beneath the water, so that it carries with it its own atmosphere. The air-bubble which invests its body gives it a strong resemblance to a globule of quicksilver, and renders it a pretty object in an aquarium as it swims about in search of food or in prosecution of its spinning operations. ”

“ Trilobites form an important part of all the faunas of the Cambrian system; they attain their greatest development in the Ordovician period, after which they become less numerous; their decline is very marked in the Devonian, in which nearly all the genera are but survivals from the Silurian period; in the Carboniferous, evidence of approaching extinction is seen in the small number of genera represented, all of which belong to one family—the Proëtidae, in the relatively few species in each genus and in the small size of the individuals of those species. ”

“ The labrum is large, and forms a chamber above the mouth, into which food is driven by the limbs, as in the Phyllopoda, food being taken while the animal swims or lies on its back. The oesophagus runs vertically to join a small stomach, which bends sharply backwards and passes gradually into an intestine. In the last segment of the abdomen the intestine joins a short, thin-walled rectum, provided with radial muscles, by means of which it can be dilated. The dilatation of the rectum leads to an inhalation of water through the anus, which may possibly serve as a means of respiration. ”

“ The tarsal joint of the male pedipalp develops a sexual organ. The abdomen is furnished with spinning mammillae.
The true Spiders can readily be distinguished from allied Arachnid groups, with which they are often popularly confounded, by the presence of a narrow constriction or “waist” between the cephalothorax and abdomen, and of a group of “spinnerets” or external spinning organs beneath the hind portion of the body. Thus the so-called “Harvest-spider” or “Harvestman” is clearly not a Spider, for there is no constriction of its body into two parts, nor does it possess any spinnerets. ”

“ The mortality among very young spiders must be exceedingly great; indeed, this is indicated by the large number of eggs laid by many species, an unfailing sign of a small proportion of ultimate survivors. We shall have, by and by, to speak of some of their natural enemies, but apart from these their numbers are sadly reduced by the rigours of the weather, and appreciably also by their tendency to cannibalism. A thunderstorm will often destroy a whole brood, or they may perish from hunger in the absence of an adequate supply of insects minute enough for their small snares and feeble jaws. ”

“ Again, some few of the eggs in an infested cocoon occasionally escape the general destruction and reach the adult condition, but there can be no doubt that Ichneumons are largely instrumental in keeping down the numbers of most species of spiders. The perils which attend the Spider after leaving the cocoon are no less formidable, and much more numerous. The whole newly-hatched brood may be destroyed by a heavy rain-storm. If there is not a sufficient supply of food suitable to their feeble digestive powers they perish of inanition, or eat one another. ”

“ The Phreatoicidae are a curious family of Isopods confined to the fresh waters of Australia and New Zealand, which bear a remarkable resemblance to Amphipods, being laterally compressed and possessing a subchelate hand on the anterior thoracic leg. These Isopods are exceedingly common in small mountain pools and in streams in Tasmania, and in the Great Lake in that country I have recently found a number of species which, together with some species of Amphipods, make up the dominant feature in the Crustacean fauna. One of these species may grow to fully an inch in length. ”

“ Since sounds are conveyed by vibrations of the air, it is never very easy to determine whether responses to sounds produced near the animal experimented upon are proofs of the existence of an auditory organ, or whether they are only perceived through the ordinary channels of touch. In any case, the organs of hearing and of smell have not yet been located in the Spider. M‘Cook considers various hairs scattered over the body of the spider to be olfactory, but from Gaskell’s researches upon allied Arachnid groups it would seem that the true smelling organ is to be sought for in the rostrum. ”

“ The course of the circulation is on the whole outwards in the inferior or ventral sinus, inwards towards the heart in the superior, save in the proboscis, where the systole of the heart drives the blood forwards in the dorsal channel. The beat is rapid, two or three times in a second, according to Loman, in Phoxichilidium. Especially in the species with small body and exaggerated legs, the movement of the circulatory fluid is actuated more by the movements of the limbs and the contractions of the intestinal caeca than by the direct impulse of the heart. ”

“ If, as is generally believed, the organ is used to warn off enemies, it is not necessary that the sound produced should be audible to the spider itself. If there be any true hearing organ in spiders its location is quite uncertain. Some have supposed the so-called lyriform organs in the legs to have an auditory function, while others have supposed the power of hearing to reside in certain hairs, of which there are several different types distributed over the body and limbs of the animal. ”

“ The asymmetry of the adult (Fig. 123, D) is now imposed upon this larva by the migration of the liver, gonads, and green glands into the abdomen, and by the shifting of the posterior lobes of the liver on to the left side of the intestine, which is displaced dorsally and to the right. The gonad lies entirely on the left side. The pleopods of the right side now degenerate, more completely in the male than in the female, and this degeneration is not completed until the little crab has found a shell and lived in it for some time. ”

“ Some only use their silk for spinning a cocoon to protect their eggs, while others employ it to make snares and retreats, to bind up their prey, and to anchor themselves to spots to which they may wish to return, and whence they “drag at each remove a lengthening chain.”
All these functions are performed by the silk-glands of the Orb-weavers, and hence it is with them that the organs have attained their greatest perfection. We may conveniently take the case of the common large Garden-spider, Epeira diademata. The glands occupy the entire floor of the abdomen. ”

“ Returning, it succeeds, by a more skilful effort, in drawing the spider from its retreat and hurling it to the ground, where, terrified and helpless, it falls an easy prey. Should the insect bungle in its first attack and become entangled in the web, it would itself become the victim. Certain wasps thus appear to seek out particular species of spiders as food for their larvae. Others are less discriminate in their tastes. Again, some, as in the cases cited above, store their egg-nest with a single spider, while others collect many for the purpose. ”