82 ARTttROPODA. 



Subclass IV. EDRIOPHTHALMA 



ARTHROSTRACA. TETRADECAPODA. 



Eyes sessile. No carapace. Head, thorax, and abdomen dis- 

 tinct, the two latter segmented. Branchiae more or less connected 

 with the legs. Sexes distinct. 



The two anterior pairs of legs [gnathopoda] are homologous to 

 the two outer pairs of foot-jaws of the Decapoda. The young 

 resemble the parent to a certain extent, and are for some time 

 protected by the mother. The principal transformations take 

 place in the egg. 



TheEdriophthalmaand Podophthalma form the Malacostraca 

 of the older authors. Dana includes Trilobita and Eotifera in 

 his Edriophthalma. Schmarda adopts the three following orders 

 of Latreille : 



Abdomen well developed. 



Respiration by thoracic vesicles AMPHIPODA. 



Respiration by foliaceous limbs ISOPOD A. 



Abdomen rudimentary L^EMODIPODA. 



Order I. L^EMODIPODA. 



Abdomen rudimentary. Branchial vesicles attached to two or 

 three thoracic rings. The first thoracic segments confluent with 

 the head ; the first two pairs of legs attached to this part. 



The dorsal portion of the segments is entire. The female is 

 furnished with abdominal laminse for retain ing the ova. Cyamus 

 is parasitic, chiefly on whales. Caprella and Proto are sluggish 

 inhabitants of our rocky tidal pools. 



Laeraodipoda are for Claus a tribe of Amphipoda. 



Caprellidce. Podalirius. 



Caprella. 



Proto. Cyamida. 



Protella. Cyamus. 



Cecrops. 



Order II. AMPHIPODA. 

 Branchiae consisting of membranous vesicles attached to the 



