. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). TYPE CRUSrACEA. 373 ilia of Noto- 11a of Cavi- ir palp. mauuer the grasping claws (Fig. 165, B) or cLeli» are devel- oped by tl'.e liexioii of the terminal joiut on the subterminal or by the elougatiou of the angles of the latter into a more or less strong process against which the terminal joint may be approximated. The description given above of the various appendages is of course general, the modifications found in the various forms being almost endless. Indeed in pa
. A textbook of invertebrate morphology [microform]. Invertebrates; Morphology (Animals); Invertébrés; Morphologie (Animaux). TYPE CRUSrACEA. 373 ilia of Noto- 11a of Cavi- ir palp. mauuer the grasping claws (Fig. 165, B) or cLeli» are devel- oped by tl'.e liexioii of the terminal joiut on the subterminal or by the elougatiou of the angles of the latter into a more or less strong process against which the terminal joint may be approximated. The description given above of the various appendages is of course general, the modifications found in the various forms being almost endless. Indeed in parasitic forms the ap- peudages, except those concerned in mastication, may entirely disappear, all gradations between fully-developed append- ages and the merest rudiments being found in various icic appeu- Fig. 166.—Sixth {A) and Second (B) TnoijAcxc Appendages op Bkanchio- POD, Apus (after Zaddach from Bronn). hr = bract. fl = Uabelluni. l~6 - iuuer lobes. From what has been said, however, it may be seen that typi- oally the Crustacean appendage may be considered a biramous structure, consisting of a two-Jointed basal portion termed the protop(,dite and two jointed branches termed the exopodite and emfopodite (Fig. 165, ex, en) accordinj,' to their relation to the median axis of the body. Additional rami are frequently developed upon the i)r()t()podite—such, for example, as that termed the cpipudife (Fig. 167, ep) and the branchia (hr). How- ever, although such a limb may be considered typical, it is not necessarily also the most primitive. Indeed wheii the simplest forms, such as the Phyllopoda, are examined it will be found that the more posterior appendages have a very clilierent composition. Thus in the genus Apm the sixth tlioracic appendage (Fig. 166, A) consists of a central two- a'—-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrat
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