CAPRELLIDAE OF WESTERN NORTH ATLANTIC 



47 



Figure 20. — Caprella septentrionalis, female; a, lateral view; b, pereopod 7; c, gnathopod 2; 



d, abdomen. 



length of basis of gnathopod 2 usiiall}'- greater than 13.0, inner surface 

 of gnathopod 2 with small tooth adjacent to poison tooth. 



Description.— Body spination variable. Length of largest male 20 

 mm, largest female 20 mm, smallest ovigeroiis female 9 mm. 



Peduncle of antenna 1 occasionally with dense setules. Length of 

 antenna 2 longer or shorter than peduncle of antenna 1. 



Mouth parts typical of genus, right lacinia mobilis 5-toothed. 



Propodus of gnathopod 1 with 2 proximal grasping spines, grasping 

 margin of dactylus and propodus serrate. Palm of propodus of gna- 

 thopod 2 wnth proxhual poison tooth and small tooth on inner surface, 

 distally with small tooth, notch, and rectangular projection, antero- 

 distal margin occasionally with projection; basis short and robust. 



Gills usually elliptical, occasionally oval and inflated. 



Propodus of pereopods 5-7 with pair of proximal grasping spines. 



Abdomen of male and female typical of genus. 



Variation. — Body spination varies from quite spinose to almost as 

 smooth as in C. linearis. Usually the cephalon is furnished with at 

 least a single spine. 



