. Text-book of zoology for junior students. Zoology. 138 1N \- KltTEBI! ATE AN I J! A LS. poseil of .1 c:)iiVL-x u]ii)ei- [ ((') and a flatter ventral arch (s), and each may supiiort a, .single pair cf appendages. Typically, each appendage in a (' ni a short basal portion or " ])ro- topodite" (tig. 80, a), which gives oi'igin to an outer and an inner branch or division, known respectively as the " exopodite " (h) and the " endopodite " (c). Very commonly one of the two divisions of the appendage may be wanting ; or in some cases both are
. Text-book of zoology for junior students. Zoology. 138 1N \- KltTEBI! ATE AN I J! A LS. poseil of .1 c:)iiVL-x u]ii)ei- [ ((') and a flatter ventral arch (s), and each may supiiort a, .single pair cf appendages. Typically, each appendage in a (' ni a short basal portion or " ])ro- topodite" (tig. 80, a), which gives oi'igin to an outer and an inner branch or division, known respectively as the " exopodite " (h) and the " endopodite " (c). Very commonly one of the two divisions of the appendage may be wanting ; or in some cases both are absent, and the ap- penilage may Ije reduced to tlie protijpodite only. A certain mnnber of the appendages of the anterior segments are usu- ally converteil into masticating organs, some of which may be proper biting jaws (mandibles and maxilhe), while others are merely limbs so far modified as to act as subsidiary jaws ("foot-jaws" or maxillipedes). Tlie l;ist segment of the budy—known as the " telson "—carries no appendages, and is often regarded as not being jiroiierly a segment, but an unpaired ;ip]iendage. The Criixt<i,-i-(i form an extremely large grouj) of animals divided into many orders, and it will be sufficient to merely notice many of these in the briefest manner. It will also be as well to commence with the consideration of the higher sections of the class .—Til. IC tliirrl . segment nf . / l)(,rsll iivli : s Vriilral r tin- sr.^niriil ; ,»liti- ; h ; I- Eiiiliii-odHr. ORIiKR JJECAPOIIA. Tile C'nixliicfa iiicludeil in this order ilerive their name from the fact that they all pussess five pairs of legs (tir. (A'/'Cf., ten ; pnji-s, feet). They lielong Uplithi(lmiitii), from the ftict that tlie eyes are sup- ]i(irteil by long, stalks. Tliey all further htive the cejihalo- tliorax covei-ed by a gi'eat sliielil or " c;ir,i]iace," under which the gills are carried. They ineln
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1885
