356 



Introditctio7i to AniiJial Morphology. 



maxillipedes and small gills. In Crangon the two pairs of 

 antennae are closely approximated. In Alpheus the inner 

 antenna is above the outer at origin, and the rostrum is small, 

 or large, serrated (Palaemon). Troglocaris, from the cave of 

 Adelsberg, is eyeless. Peneus, with small rostrum, has a 

 distinct nauplius stage. 



Fig. 41. 



Hippolyte Gordoniana. 



Sub-order 2, kxiOTxm.x2.{M. Edwards) — post-abdomen small, 

 nearly, or quite limbless, with soft terminal processes, not sunk 

 into a sternal hollow : pterygostomial regions isolated by a 

 suture from the cephalostegite ; the fifth, or fourth and fifth, 

 pair of pereiopods aborted; the last maxillipede large; the larva 

 is a Zoea (see next order). The families are : — i. Hippidae — 

 with a long cephalothorax ; and 2 . Lithodinidse — with a crab-like 

 cephalothorax; both these have a hard-shelled post-abdomen. 

 3. Galatheidae have large chelae and a roundish (Porcellana) 

 or elongate (Galathea) cephalothorax, a moderate post- 

 abdomen, and tail-fin. 4. Paguridae — hermit crabs, have un- 

 equal chelae, round, soft, post-abdomen, with a terminal 

 sucker, imbedded plates, and 2-3 pair of soft, fin-like, rudi- 

 mental feet; they hide this part in the deserted shells of 



