250 



GAMMA.RID.E. 



AMPHIPODA. 

 NATATOItLl. 



GAMMARIDES. 



ATYLUS BISPINOSUS. 



Specific character. First and second segments of the pleon posteriorly pro- 

 duced into two strong dorsal teeth. Latero-posterior margin of the third 

 segment ornately waved and serrated. 



Length \ inch. 



SPENCE BATE, Ann. Nat. Hist. 2 ser. xix. p. 142, 1857. 



WHITE, Pop. Hist. Brit. Crust, p. 178. 

 SPENCE BATE, Cat. Amph. p. 140, pi. xxvii. fig. 1. 



Atylus bispinosus. 



THE head is anteriorly produced, between the superior 

 pair of antennae, into a small rostrum. The first two 

 segments of the tail have the postero-dorsal margins pro- 

 duced into two strong teeth ; the third segment of the 

 tail has the posterior margin considerably waved on each 

 side: commencing from the middle of the back, it is 

 first concave, then produced on each side into a small 

 lobe ; it is again deeply sinuated, the lower edge of the 

 sinus produced in the form of a strong recurved tooth, 

 below which it is indented, the margin being closely ser- 

 rated to the inferior angle, which terminates in a sharp 

 tooth. 



