xlvi 



Adversum, 194. 

 Subulalum, 194. 



PLEUROTOMA (q). 

 Gracile, 195,/ 40. 

 Sinuosum^ 195. 

 Septangulare, 196. 

 Boothii, 196. 



Linear -e, 197. 

 Trevellianum, 1 97,/5 1 (r) 

 Smithii, 198. 

 Coarctatum, 198. 

 Decussatum, 198. 

 Reticulatum, 199. 

 Metcalfei (s). 



.(q) The two first species alone possess the constant 

 emargination which should distinguish this genus. The 

 others have a more or less distinct sinus, and will pro- 

 bably form a subgenus with the first 8 or 9 species of 

 the second division of our Fusi, to which they are so 

 closely allied that it is impossible with justice to sepa- 

 rate them. But as these latter cannot come within the 

 definition of Pleurotoma we have provisionally fol- 

 lowed Turton in our arrangement. 



(r) Will probably prove but a variety of F. Turri- 

 cula, the depth of the sinus evidently varying in indi- 

 vidual specimens. 



(s) P. METCALFEI, Reeve MSS. Elongated-sub- 

 fusiform, white, with a single subcentral rather broad 

 brownish band on the body-whorl, which runs along 

 the base of the others ; whorls 5, not raised, but the 

 suture distinct; adorned with 6 broad, strong, and ele- 



