CRUSTACEA OF ALABAMA. 39 



FAMILY BRANCHIPODID^E. 



Genus Streptocephalus, Baird. 

 The largest and most interesting species of the genus is 



Streptocephalus sealii, R y der - 



(Plate VI, Fig. 2.) 



which occurs throughout the eastern and southern states. These are very beautiful ani- 

 mals, brilliant in color and graceful in motions. They are abundant in pools of northern 

 Alabama and also about Mobile, where myriads were seen with Cypris perelegans. Sev- 

 eral stages in the development were observed, showing that the animals do not take on 

 the final form for some time after they are sexually mature. The caudal stylets of the 

 male form the most perfect possible clasping apparatus, being thorny instead of clothed 

 with weak pectinate hairs, as in the female. This is the more remarkable as the anten- 

 nae as conspicuous examples of clasping organs as can be imagined. 



Genus Chirocephalus, Prevost. 

 Chirrocephalus holmani, R )' d, ' r - 



The young of this species was found with Streptocephalus in northern Alabama. 



CRUSTACEA TETRADECAPODA. 

 (Fourteen-footed Crustacea.) 



ORDER ISOPODA. 

 (The Pill-bugs.) 



The Isopoda are well represented in Alabama, but are as yet quite unstudied. The 

 collection made by the writer has been mislaid and the only data available are the draw- 

 ings reproduced in Figs. 8-9, of Plate V. 



Genus Asellus, Geoff. 



First pair of feet chelate, last thoracic legs not elongate, first two pairs of abdomi- 

 nal appendages in male and first pair in female lamellate, small, caudal stylets elongate, 

 mandible with a palp. 



