372 Messrs. Brady and Robertson on Dredging 



nograph,' we now give drawings. It seems to be of very rare 

 occurrence, and we have had no opportunity of seeing the 

 animah 



Hah. Westport Bay, 4 fathoms. 



Genus Sclerochilus, G. O. Sars. 

 SderocMlus (?) gracilis^ uov. sp. PI. XX. figs. 11, 12. 



Carapace, as seen from the side, elongate, subtriangular, highest 

 in the middle ; height much less than one-half of the length ; 

 extremities narrowly rounded : superior margin boldly 

 arched, somewhat flattened in the middle ; inferior straight, 

 with a slight median sinuation. Seen from above, com- 

 pressed ovate, widest in front of the middle, extremities 

 pointed ; width equal to one-third of the length. Shell per- 

 fectly smooth, milk-white. Length Vt inch. 



Hob. At Westport, in company with Gythere gihhosa. 



SclerocMhis contortus^ var. abhreviatus. PI. XX. figs. 15, 16. 



This seems to bear much the same relation to the normal 

 form of S. contortus as Paradoxostoma abbreviatum does to 

 P. variabile] but, from the small number of specimens yet 

 observed, we hesitate to describe it as a distinct species, not 

 having been able to investigate the anatomy of the animal. 



Hab. Clifden Bay, above low-water mark. 



Fam. PolycopidsB. 



Genus PoLYCOPE, G. O. Sars. 



Polycojye compressttj nov. sp. PI. XXI. figs. 5-11. 



Carapace, as seen from the side, almost circular, the length 



being but slightly greater than the height. Seen from 



above, compressed, oblono-^ widest in front of the middle ; 



width scarcely equalling half the length, rounded in front, 



obtusely pointed behind. Surface of the shell perfectly 



smooth ; colour yellowish white. The free margins of the 



valves are minutely denticulate, with about fifteen small 



sharp teeth. Diameter -^ inch, 



Hab. Clifden Bay, in 4 fathoms, on a fine gravelly bottom ; 



also off Eddystone Lighthouse ; and in a gathering from 



the harbour of Messina, about 8 fathoms, for which v, e are 



indebted to the kindness of Dr. Dohrn. 



The much more compressed character of the valves, the 



denticulated edges, and absence of surface-sculpture at once 



distinguish this from the only hitherto described sjx'cies of the 



genus, P. orbicidan'ft. Several specimens were captured ; and 



