. The microscope and its revelations. rs attached to it, constitutes nearlythe whole bulk of the animal. The head is extended in front into 1 It is remarkable that very large forms of this group, sometimes extending tomore than twelve inches across, have been brought up from great depths of the sea. 958 CRUSTACEA a proboscis-like projection, at the extremity of which is the narroworifice of the mouth, which draws in the semi-fluid aliment. Insteadof being furnished (as in the higher crustaceans) with two pairs ofantenna? and numerous pairs of foot-jaws, it has but a single pairof either; it al
. The microscope and its revelations. rs attached to it, constitutes nearlythe whole bulk of the animal. The head is extended in front into 1 It is remarkable that very large forms of this group, sometimes extending tomore than twelve inches across, have been brought up from great depths of the sea. 958 CRUSTACEA a proboscis-like projection, at the extremity of which is the narroworifice of the mouth, which draws in the semi-fluid aliment. Insteadof being furnished (as in the higher crustaceans) with two pairs ofantenna? and numerous pairs of foot-jaws, it has but a single pairof either; it also bears four minute ocelli, or rudimentary eyes, setat a little distance from each other on a sort of tubercle. Fromthe thorax proceed four pairs of legs, each composed of several joints,and terminated by a hooked claw; and by these members theanimal drags itself slowly along, instead of walking actively uponthem like a crab. The mouth leads to a very narrow oesophagus(a), which passes back to the central stomach (b) situated in the. FIG. 719.—Anvmothea pycnogonoides: a, narrow oesophagus;b, stomach ; c, intestine ; (I, digestive Cffica of the foot-jaws ;e, e, digestive c-eca of the legs. midst of the thorax, from the hinder end of which a narrow intes-tine (c) passes off. to terminate at the posterior extremity of thebody. From the central stomach five pairs of c;tjcal prolongationsradiate, one pair (d) entering the foot-jaws, the other four (e, e)penetrating the legs, and passing along them as far as the last jointbut one ; and those extensions are covered with a layer of brownish-yellow granules, which are probably to be regarded as a digestivegland. The stomach and its ca?cal prolongations are continuallyexecuting peristaltic movements of a very curious kind ; for theycontract and dilate with an irregular alternation, so that a flux andreflux of their contents is constantly taking place between thecentral portion and its radiating extensions. The perivisceral spaceI>H
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
