Introduction to Animal Morphology. 359 



rings ; one gill only is attached to the first maxillipede, under 

 the pleura ; there are no chelae nor eyes ; the inner antennae 

 are small, bicirrose, the outer large in the male, small in the 

 female ; the limbs shorten from before backwards, the four 

 anterior in the males, and the first, or first and second in the 

 female, have swimming appendages ; the gills are simple ex- 

 pansions of the organs in Zoea, to which larval form this is 

 the nearest mature ally ; the eggs are large and few, and the 

 larva emerges one-fourth the size of the mother. 



2. Lsemodipoda {Laireille) — post-abdomen rudimental, 

 with obsolete appendages ; head fused with the first thoracic 

 ring, so that the front feet appear to be jugular. There are five 

 pair of clawed feet, the third and fourth pair represented only 

 by membranous gills on the bisegmented abdomen ; the 

 mandibles have no palps ; the maxillae are two-jointed. Two 

 families are included: — i. Cyamidae, whale-lice — body flat, 

 oval ; head small ; upper antennae four-jointed ; gill vesicles 

 on the abdominal segments in the female utilized as egg- 

 bearers ; maxillipedes united into a labium, and bearing palps. 

 2. Caprellid^e — body free, jointed, slender, with long three- 

 jointed antennae ; penultimate joints of the first and second 

 limbs thick ; third and fourth absent ; fifth, sixth, and seventh 

 pair long. 



Order 3. Amphipoda {Lamarck) — head and prothorax 

 united, covered by a horny shell ; segments nearly homono- 

 mous, laterally compressed ; limbs seven pairs, two thoracic, 

 and five abdominal ; one pair of maxillipedes forming a lobate 

 under lip ; second and third pair of thoracic limbs prehensile ; 

 the four anterior abdominal are gill-bearing ; post-abdomen 

 with seven segments, and several feet with bristle appendages ; 

 the three hinder pair of abdominal feet are concave forwards, 

 the others are convex forwards, hence the name ; stomach 

 with gizzard plates, and one or two pair of hepatic caeca ; de- 

 velopment is without metamorphosis. In the egg there is 

 formed a larval membrane, separate from the chorion and 

 inner egg-membrane, the remains of the nauplius carapace, 

 which is lost at birth ; a heap of cells extends from this to 

 the back of the embryo (micropyle apparatus of Meiss7ier), 



