I. '08. 119 



General (Jisfrihution. — The type specimens were found oif 

 the east coast of N. America/ 35° 45' N., 74° 31' W., and 

 39° 35' X., 71° 24' W. (Smith). More recently it has been 

 taken by the Danish-Ingolf Expedition in Davis Straits and 

 near Iceland (Hansen). 



Irish distribution. — The single record is as follows : — 



Helga. 



S.R. 497— 10/9/W.— 51° 2' N., 11" 36' W. 775-795 fathoms. 

 Trawl— One 19 mm. 



Vertical range. — 393 fathoms (Hansen) to 1,043 fathoms 

 (Smith). 



Family ALPHEIDAE. 



Two genera, Alphens and Athanas, are known from British 

 and Irish waters : — 



I. Rostrum very short ; eyes wholly covered in dorsal 

 view by the projecting anterior margin of the 

 carapace ; outer antennule uniramous ; anten- 

 nal scales reduced ; no articulated process on 

 the sixth somite at the base of the uropods, 



Alpheiis (p. 120). 



II. Rostrum comparatively long ; eyes only partially 

 covered in dorsal view by the projecting an- 

 terior margin of the carapace ; outer antennule 

 biramous for more than half its length ; an- 

 tennal scales well developed ; an articulated 

 process on the sixth somite at the base of the 

 uropods, . . . ... Athai^as (p. 122). 



The branchial formula of these two genera is expressed in 

 the following table : — 





! vn. 



vin. 



IX. 



X. 



XT. 



xn. 



XTTT 



XR'. 



t 



Podobranchiae, 



.. ep. 



ep. 



ep. 



ep. 



ep. 



ep. 



+ep. 



... ! 



Arthrobranchiae, 





... 



... 













Pleurobranchiae, 







... 



1 



1 



1 



1 



1 



The epipod at the base of the penultimate pair of pereiopods 

 is present in Alphens ruber but absent in Athanas nitescens. 



