. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). 436 INVERTEBRATE MORPHOLOGY. 5- '1! JjS. may be united with the cephalothorax. In the Scorpions it is divisible into an anterior portion, the prseabdomeu, much broader and stouter than the posterior postabdomen, an ar- rangement also indicated in certain other forms. In the adults the abdomen is usually destitute of appendages, though they may be present in the embryos; the Scorpions, however, possess two highly-modified pairs, and it seems probable that the four or s
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). 436 INVERTEBRATE MORPHOLOGY. 5- '1! JjS. may be united with the cephalothorax. In the Scorpions it is divisible into an anterior portion, the prseabdomeu, much broader and stouter than the posterior postabdomen, an ar- rangement also indicated in certain other forms. In the adults the abdomen is usually destitute of appendages, though they may be present in the embryos; the Scorpions, however, possess two highly-modified pairs, and it seems probable that the four or six papilliD upon which the ducts of the spinning- glands open in the Spiders represent also modified append- ages. A special respiratory system is entirely wanting in a few forms. In the majority there occur on the sides of the body from one to four pairs of pores termed stigmata (Fig. 201, st^'^). In the Scorpions and some other forms each stigma opens into a cavity lined with cliitiu continuous with that which covers ^ the general surface of the body, f and into this cavity there project * a number of lamellae arranged ^ like the leaves of a book (Fig. ^ 199), whence the term lung-books frequently applied to them. Each lamella is hollow, trabecular ex- tending across the cavity troiii one wall to the other, and the cavities communicate with tlie c, so that blood can readih' flow into them and so cliange its gases through the thin TiiRonim TiiK Li'No-BooK OF Avails of the lamellro. In otln'V SimDKK (lifter McLkod). cases there occurs in connection ch = rliitino,j,'(Mious tiHsue. ^^itj^ the lung-book apparatus, or ff = ImmIv Willi. , J- 1 1 ⢠-i 1 , ,â , â else entirely rei) acing it, a tia- «( = stigma. choal system consisting of a niini- t = lust coinpnrtnipnt of Iupg:- bor of tubes ramif^'ing thron^li book, In clmr- tlio l,ody. Ill some cases a stron.^ tube or trachea arises at each ntigiiiti jxuii iTaverses tne ixjily, giving s>ii ijriiiiclieH to
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1896
