358 IntrodiLction to A n inial Morphology. 



six. The carapace is pyriform in Dorippe, semicircular in 

 Calappa, round in Matuta, globular in Leucosida, obversely 

 pear-shaped in Ranina. 



Order 2. Stomapoda [Lamanli) — marine, with thin chi- 

 tinous shell ; gills branched, free at the base of the pleiopods, 

 or none (Mysis), rarely on the cephalothoracic legs ; the 

 hinder thoracic resemble the anterior abdominal legs ; the 

 tail has a broad swimmeret attached to the last somite ; de- 

 velopment is from a Zo'ia. There are three families : — 

 I. Schizopoda — Omostegite reaching to the beginning of 

 the post-abdomen, and in front covering the antennae and 

 eye pedicles ; outer antennas arising below the inner ; all 

 legs sub-equal ; gills none (Mysis), or on all the eight thora- 

 cico-abdominalfeet(Thysanopus). 2. Leuciferina — carapace 

 small, but reaching to the post-abdomen ; in front of it is a 

 long head-process, on which the antennae, antennules, and 

 eyes are seated ; the four hinder pair of limbs are sim- 

 ple, slender, and the post-abdomen linear. 3. Squillina — 

 long, with small cephalothoracic shield, leaving the front of 

 the head and the hinder abdominal rings free ; gills on the 

 post-abdominal legs ; the second pair of thoracic legs large, 

 its comb-like last joint shutting into a groove in the penulti- 

 mate joint, like a penknife blade ; the heart is long. 



CHAPTER XLIII. 



SUB-CLASS 8. — EDRIOPTHALMIA {Leach). 



Small, but not microscopic Crustacea, with twenty 

 body-somites, compound, sessile eyes, and rarely a 

 carapace. Four orders are included : — 



I . Cumacese {Kroyer) — marine, uniting many of the cha- 

 racters of Schizopoda with those of Edriophthalm s ; the 

 short cephalothorax does not cover the hinder abdominal 



