514 BULLID.E. 



C. MAMMILLATA, Pllilippi. 



Minute, smooth ; suture canaliculated ; apex mammillary ; 

 spire visible ; more frequently projecting. 



Plate ex IV. c. fig. 4, 5. 



Bulla mammillata, Philippi, Moll. Sicil. vol. i. p. 122, pi. 7, f. 20 ; vol. ii. p. 96. 

 — Jeffreys, Ann. Nat. Hist. vol. xix. p. 310. — Thomp- 

 son, Ann. Nat. Hist, new ser. vol. iii. p. 351. 

 „ {Tornatina) mammillata, A. Adams, Sower. Thesaur. Conch, vol. ii. p. 5 GO, 



pi. 121, f. 26. 

 „ trimcalula, Jeffreys, Ann. Nat. Hist. vol. xix. p. 310 (var. with sunken 

 apex.) 



Still more minute than iruncata this cylindrical little 

 shell exhibits so much of the general aspect of that species, 

 that the absence of the posterior sulci, and the peculiarity 

 of its apex are the only salient points in which it differs. 

 The surface is smooth or merely substriated lengthways 

 (under the microscope very perfect examples are substriated 

 in a spiral direction) ; the body does not taper above, but 

 is broadly though shallowly retuse in the middle, the upper 

 area being as wide as the lower one. The crown is sub- 

 truncated (yet the upper edge of the body is well rounded), 

 and is at most barely surmounted by a rather large mam- 

 millary apex, besides which a second volution almost level 

 with the top of the body is often visible ; sometimes, how- 

 ever, that turn, or even both, is so sunken as not to be 

 apparent ; in the former case the sutural line is narrow and 

 canaliculated ; in the latter event the nipple seems encir- 

 cled by a broadish fosse. The top of the aperture is usually 

 on a level with or above the apex ; its opposite extremity is 

 much dilated but not bulbous, as the columella, whose fold 

 is not distinctly pronounced, slants to the left in a straight- 

 ish line. There is no umbilicus behind it, but the pillar 



