142 PROCEEDINGS OF THE ACADEMY OF [1889. 



Cytherea Penistoni. PI. VIII, fig. 4. 



Shell sub-trigonal, the beaks prominently elevated; lunule cordi- 

 forni ; the dental characters normally those of the genus; anterior 

 lateral tooth (left valve) triangular, lamellar. 



Margin of shell even ; pallial sinus broad, directed upwards, and 

 not quite reaching the centre of the shell. Lines of growth closely 

 set, and even. Shell covered with a chestnut epidermis ; interior 

 purplish. 



Length '6 inch ; height "5 inch. 



It gives me pleasure to name this delicate, and abundantly 

 represented, Cytherea after my friend Miss A. Peniston, of Peniston's, 

 from whom I have received much valuable assistance in the prepara- 

 tion of my material illustrating the Bermudian fauna. 



Emarginula dentigera. PI. VIII, fig. 7. 



Shell flattened, scutiform, broadened posteriorly, and with the 

 apex slightly sub-central ; surface with radiating ribs, which alter- 

 nate in size — sometimes two smaller ones between each pair of large 

 ribs — and project (the larger ones) prominently beyond the general 

 margin. The impressed concentric lines give to the ribs a knobbed 

 appearance. Fissure fairly long, narrow. 



Length nearly # 25 inch ; height - 1 inch. 



Emarginula pileum. PL VIII fig. 6. 



Shell elevated, with the form of a Phrygian cap ; apex largely 

 posterior, well beaked; radiating lines alternate, deeply impressed by 

 the concentric lines of growth, and appearing knobbed. Fissure 

 moderately long, parallel-sided, and occupying the position of one of 

 the larger ribs. 



Length slightly exceeding a quarter of an inch ; height *2 inch. 



Caecum termes. PI. VIII, fig. 5. 



Shell arcuate, gradually increasing in size anteriorly, where it is 

 somewhat swollen ; surface longitudinally-costated, the costse appear- 

 ing slightly rugose near the swollen base through the passing of the 

 lines of growth. Mucro distinct, well excentric. 



Color of shell yellowish ; surface glossy. 



Length about '1 inch. 



This form appears to be fairly abundant. It may be readily dis- 

 tinguished from most of the other longitudinally-costated species by 

 the very nearly equal diameter of the shell, being only slightly 

 swollen basally. 



