Text-book of comparative anatomy . nidce (Fig. 379, p. 538), 4 pairs in the Chernetidce and 4 pairs in the Arancidcc (, p. 539). Such rudiments of abdominallimbs will probably also be found in theembryonic stages of other Arachnoidea, whosedevelopment has been hitherto not sufficientlyinvestigated. 2. The Scorjiionidce possess in the adultcondition on each side of the second abdo-minal segment ventrally a comb-like organ(Fig. 362, &), whose function is not yet fullyknown. These two combs are said tocome from embryonic rudiments of the limbsof the second abdominal segment. 3. It is in th
Text-book of comparative anatomy . nidce (Fig. 379, p. 538), 4 pairs in the Chernetidce and 4 pairs in the Arancidcc (, p. 539). Such rudiments of abdominallimbs will probably also be found in theembryonic stages of other Arachnoidea, whosedevelopment has been hitherto not sufficientlyinvestigated. 2. The Scorjiionidce possess in the adultcondition on each side of the second abdo-minal segment ventrally a comb-like organ(Fig. 362, &), whose function is not yet fullyknown. These two combs are said tocome from embryonic rudiments of the limbsof the second abdominal segment. 3. It is in the highest degree probablethat the spinning mammilla? of the Aranei</<)they are for the most part jointed ; (b) they,as recently observed, develop from the em-bryonic rudiments of abdominal limbs ; (c) thefact that they are spinning mammillae, the spinning glands open on FIG. 362. — Buthus occitanus (Regneanimal). Cephalo-thorax, pre - abdomen(pra), and the first segments of the post-tracheata and Antennata, and particularly the abdomen (ya), from the ventral side. Limbs These facts gather weight when we rememberthe coxal and spinning glands of the Pro- slime papillae of Peripatus and the spinneretsof Scolqpendrella. The assumption that the not fully drawn. 1, Chelicerse; 2,pedipalps (jaw-feelers, chelate-feelers) ; g,genital aperture ; s, stigmata ; 1;, combs. spinning mammillae of the Cyphophthalmid genus, GibboecHuin, also represent rudimentary limbs, is open to the objection thatthe two pair of mammillae lie in one and the same, the 2d abdominal segment. 1 See note on p. 516. 518 COMPARATIVE ANATOMY CHAP. The occurrence of rudimentary abdominal limbs in the Arachnoidea proves thatthe ancestors of these animals possessed extremities on the abdomen (at least on 6abdominal segments). II. The Nervous System. The segmentation of the body is refl
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
