102 AMERICAN MARINE CONCHOLOGY. 



epidermis yellowish ; spire obtuse, elevated ; suture canaliculate ; 



aperture narrow above, wide and rounded below ; outer lip sharp, 



entire, advanced in the central region, with a fissure posteriorly. 



Length 3, diam. 1.5 mill. 



Casco Bay, Me. 



This species has not been figured, and I am not acquainted 

 with it ; nor has it been found since the date of the original de- 

 scription. 



2. B. solitaria, Say. Fig. 206. 



Journ. Philad. Acad., ii. 245. 1832. 

 Bulla insculpta, Totten, Am. Journ. Sci., xxviii. 350, f. 4. 1835. 



Shell small, thin, fragile, pellucid, oval, impressed at the top, 

 with numerous microscopic revolving lines; spire none, but in its 

 place a pit ; aperture narrowly linear above, wide below ; umbili- 

 cus none ; white. 



Length 9, diam. 6 mill. 



Whole Coast. 



3. B. occulta, Mighels and Adams. Fig. 207. 



Proc. Bost. Soc. Nat. Hist., i. 50. 1841. 

 Bulla Bernhardt, Moller, Ind. Moll. Green., 6. 1842. 



Shell small, of a dingy-white color, ovate-cylindrical, covered 

 with very minute transverse strise, and with indistinct striae of 

 growth ; spire concealed ; labium extends a little below the spire, 

 nearly straight above the centre, regularly rounded below and at 

 base ; aperture narrow at the upper part, rather broad at the base. 



Length 5, diam. 3.15 mill. 



New England to Greenland. {Eur.) 



Mr. Jeffreys says this is identical with Oylichna striata, Brown, 

 1827. 



Genus CYLICHNA, Loven. 

 Ind. Moll. Scand. 10. 1846. 



In this genus the tentacular lobes are connate, indistinct ; 

 eyes sessile on their front bases ; mantle with a thick posterior 

 lobe, partially closing the aperture of the shell. 



The species chiefly inhabit deep water, and the genus is of 

 world-wide distribution. 



1. C. alba, Brown. Fig. 208. 



{Volvaria.) Brit. Couch., 3, t. 88, f. 43-44. 1827. 

 Bulla triticea, Coutliouy, Bost. Journ. Nat. Hist., ii. 88, t. 2, f. 8. 1838. 

 Bulla corticata, Moller, Iud. Moll. Green., 6. 1842. 



Shell polished, cylindrical, rather solid ; spire slightly de- 



