106 B. IV. KwikeL 



Caprellidae. 



Body slender, first antennae much longer than second. Gills 

 saclike and confined to the second, third, and fourth, or to only the 

 third and fourth thoracic segments. 



Abdomen of 5 joints at most, of which the first 3 are very short 

 and do not bear appendages ; uropods rudimentary or obsolete. 



Non-parasitic in habit. 



Cyamidae. 



Body broad and flat ; third and fourth thoracic segments without 

 limbs, posterior segments with prehensile limbs. 



Both pairs of antennae 4-jointed, first pair much longer and stouter 

 than second. 



Gills confined to third and fourth thoracic segments, elongated in 

 form. 



Parasitic on Cetacea. 



Key to the genera, of the Caprellidae. 



Mandibles without palj) Caprella 



Mandibles with palp Protellopsis 



Caprella equilibra Say, 1818. 



1818. Say, Journ. Acad. Natur. Sci. Phil, vol. 1. p. 374-401. 



Eyes compound, moderate in size. Rostrum al^sent. Body with 

 smooth dorsum. 



First antennae with peduncle stout, having third joint longer than 

 first and second longer than third ; flagellum abruptly narrower than 

 peduncle, made up of about 12 joints, less than ^/s as long as ped- 

 uncle. Second antennae fringed with long setae ; flagellum made 

 up of 2 joints, nearly as long as fourth joint of peduncle which is 

 as long as fifth, provided with long setae, terminal joint small. 



Mandibles without palp ; cutting edge divided into about 5 acute 

 teeth ; spine row with 2 or 3 stout plumose spines ; molar tubercle 

 strong, with a triangular process which gives it an irregular shape in 

 the side view. Lower lip with principal lobes widely dehiscent; 

 inner lobes fairly large ; mandibular processes narrow, rather wideh* 

 dehiscent. First maxillae with no inner plate ; outer plate cur^'ed, 

 shorter than palp, with distal margin furnished with 7 forked tooth- 

 like spines ; first joint of palp short ; second widening toward dent- 

 ated, obliquely rounded apex which is provided with many setae 

 on margin and with row of longer ones on surface near apical 



