408 



INVERTEBRATE MORPHOLOGY. 



sixth abdominal segment 

 bears a pair of biramous ap- 

 pendages with a long single- 

 jointed protopodite, the re- 

 maining segments being in 

 the female destitute of ap- 

 pendages, but in the male the 

 anterior 2 {Diastylits), 3, or 5 

 ( Oampylaspis) segments may 

 bear biramous swimming-feet. 



The lateral eyes are never 

 stalked and may be closely 

 approximated or even fused 

 on the dorsal surface of the 

 cephalothorax. They are 

 generally composed of but 

 few ommatidia and in some 

 species are entirely wanting. 



The Cumacea are exclu- 

 sively marine and are more 

 especially characteristic of 

 the colder seas. 



3. Order Stomatopoda. 



As in the Cumacea the 

 carapace covers only some of 

 the anterior thoracic seg- 

 ments, the last three or four 

 remaining distinct, but the 

 abdomen, instead of being 

 slender, is even stouter than 

 the thorax and ends in a ter- 

 minal tail-fin. The anterior 



Fig. im.-Bia.tyUs stygia, MALE'ofte.- P^'^*^^'^ °^ ^'^^ ^^'^^' ^^^^ing 

 Saks from Lang). the eyes and the two pairs 



a, = anteunule. «re=endopodite. of antennsB, is separated from 



fta = antenna. 

 ai=: abdominal ap 



pendages. 

 c<A= carapace. 



ea: = exopodite. , , , 



;)= abdominal ap- and movable upon the rest of 



7F-Fi/r= uracic *^^ cephalo-thorax, and only 

 segments. the more anterior thoracic 



