262 MAZATLAN UNIVALVES 



OEDEE PECTESTIBEANCHIATA. 



SUBOEDEB EOSTEIFEEA. 



FAMILY YAOTCOEIDJE. 



GENUS VANICOEO, Quo?/ $ Gaim. 



Vanikoro, Quoy fy G-aim., Voy. a prima manu ; (postea Sigaretus 

 seu VelutinaJ Gray, Proc. Zool. Soe. 1847, p. 156, no. 256. 

 H. $ A. Ad. Gen. vol. i. p. 374. 



Narica, Red. in Sagr. Cub. Moll. 1836, teste Phil. JIandb. 

 Conck. p. 184. "M. Eecl. lias the intention to form a genus," 

 D'Orb. Cuba, vol. ii. p. 39 : genus constituted, 1844: teste 

 Gray. 



Merria, Gray, Zool. Seech. Voy. 1839, p. 137, (anim. descr.) 



Leucotis, Swains. 1840, Treatise, p. 346. 



^ 330. VANICOEO CBYPTOPHILA, n. s. 



V. t. parvd, Sigaretoided, tenui, albidd ; nucleo awfr. iii. 

 quorum primus planatus, alteri subturriti, tenuissiine striati, 

 decliviter sito ; anfr.normalibus ii. rapide augentibus,subplana- 

 iis, irregularity striulis spiralibus creberrimis et striis incre- 

 menti, interdum his, interdwn illis superantilus, tenuissime 

 cancellatis ; apertura valde expansa, vix peripkeriam penul- 

 timam attingente ; labro elongato, labio recto ; umbilico maxima ; 

 peripherid angustiore. 



This little creature resembles the Calyptrseidge in its seden- 

 tary habits, frequenting the burrows of worms, &c. in Spondylus 

 and Chama valves, where its flattened form and advanced lip 

 (in this respect resembling Trochita) allow it to live in a very- 

 narrow space. Many specimens were ( found in situ, but there 

 was no trace of operculum. A minute shell of one whirl (found 

 inside the mouth of another,) is perfectly formed, like a tumid 

 Planorbis. Another, which was adhering over tke umbilicus of 

 an adult, is just preparing to commence the normal portion, 

 and is shaped like a Bithinia. It then lays its spire sideways, 

 but not always at the same angle, and begins a flattened 

 Sigaretoid growth. The sculpture is extremely variable, 

 sometimes nearly evanescent. Most of. the 85 specimens found 

 were very small; the nuclear shell measures *02 by '016; a 

 remarkably large specimen measures long. '15, lat. '17 by 15. 



