2l8 ON COPEPODA AND OTHER CRUSTACEA 



able to isolate them. Dr. Scott, of the Scottish Fishery Board, 

 has taken and described specimens found in the Firth of 

 Forth, where, however, he states that they are scarce. The 

 Northumbrian specimen agrees exactly with those figured by 

 Scott, except in the absence of numerous setae which have no 

 doubt been abraded in the process of capture. 



Genus THALESTRIS, Glaus. 

 Thalestris robusta, n. sp. (Plate V., figs. 11-17). 



Male, — Antennules (fig. 11) seven-jointed, the third joint 

 short and much narrower than the second and fourth, as is 

 usual in the males of this genus : hand of the posterior foot- 

 jaw ovate (fig. 12), and bearing a slender curved apical claw, 

 which is finely ciliated along its inner margin; first pair of 

 swimming feet (fig. 13) very stout, the two branches of nearly 

 equal length, their outer margins fringed with short setse, 

 terminal claws strong, falcate, and pectinated on their concave 

 margins; inner branch of the second pair of feet (fig. 14) 

 bearing a long spine-like seta at the apex of the second joint, 

 third joint much narrower and bearing slender setae; inner 

 branches of the third and fourth feet (fig. 15) much shorter 

 than the outer branches; fifth pair (fig. 16) densely setose, and 

 bearing also several strong spine-like setse, inner lobes shallow, 

 only slightly produced, outer lobes moderately long and ovate. 

 Gaudal stylets robust, scarcely as long as broad (fig. 17), 

 terminal setae very stout ; angles of the abdominal somites and 

 of the caudal stylets fringed with stout hairs. 



This species occurred in a gathering from tidal pools at 

 Gullercoats, and though only one specimen was found, the 

 characters are so distinct and well marked that I cannot 

 hesitate as regards its claim to specific rank. The animal is 

 very minute, but I unfortunately have no record of its 

 measurement. 



Thalestris denti, n. sp. (Plate VI,, figs. 10-15). 



Male. — Antennules five-jointed, very robust, of nearly equal 

 thickness throughout, excepting the third joint, which is much 

 narrower than the rest (fig. 10), last joint truncated at the 



