Text-book of comparative anatomy . rmof the adult animal are the remaining trunk segments and the 2 posterior trunk feet,all of which form during successive moults. The 2 pairs of maxillipedes which areseparately inserted on the body, and are characteristic of the adult Copcpoda inreality only correspond with the branches of the 2d pair of maxillae from which theycome, and thus strictly speaking represent but one pair of extremities. VOL. I 2 C 386 < -MPARATIVE AX A TUMY CHAP. We thus again see that in the Copepoda also the body with its limbs becomesprogressively differentiated from before
Text-book of comparative anatomy . rmof the adult animal are the remaining trunk segments and the 2 posterior trunk feet,all of which form during successive moults. The 2 pairs of maxillipedes which areseparately inserted on the body, and are characteristic of the adult Copcpoda inreality only correspond with the branches of the 2d pair of maxillae from which theycome, and thus strictly speaking represent but one pair of extremities. VOL. I 2 C 386 < -MPARATIVE AX A TUMY CHAP. We thus again see that in the Copepoda also the body with its limbs becomesprogressively differentiated from before backward. Inasmuch as all the limbs of theadult animal are fully and typically developed, we find in this case, during thedevelopment, no reduction of limbs once ( in larval stages) strongly developed. Development of Sacculina (Order Cirripedia, Sub-order Rhizocephala). The comparison of the process of development in free-living Entomostraea withthat in the parasitic forms is very instructive. Let us take that Crustacean form. FID. 2 —Various larval stages of Sacculina Carcini. -4, Nauplius after the first moult. S,Cypris stage from the side. C, The same, 3 hours after the larva has by means of its adheringantennse attached itself to a seta of the host. I), Formation of the Kentrogon larva. E, nit-same completed, the Cypris larval shell thrown off. F, The arrow has bored through the chitin-iuscarapace of the host. The contents of the sac begin to pass into the body cavity of the host throughthe arrow, fs, frontal sensory organ ; ua, Nauplius eye ; gl, glands of the frontal horns ; ov, rudi-ment of the ovary; /, fat globules ; 6, seta of the host, to which the parasite has attached itself bymeans of its adhering antennae ; pf, arrow of the Kentrogon stage ; ab, abdomen (after Delage). which in an adult hermaphrodite condition is the most degraded and deformed, (Figs. 208, 248). Although the adult animal cannot be recognised as aCrustacean, the series of
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
