Cyclostrema, Adeorbis, Vitrinella, and related genera. 1 05 



Separatista Gray, 1847 (not described), A. Adams, 1850. Type, S. separatista 

 (Chem.) Dillw. = S. Chemniizii A. Adams. Philippines. 



" Shell orbicular, somewhat discoid, the first whorls contiguous, 

 the last disunited ; aperture wide-spreading, angulated ; umbilicus 

 large, inf undibuliform, the whorls visible within as far as the apex." 

 P. Z. S., p. 45, 1850. 



Two species were described, S. Grayii Ad., from the Cape of 

 Good Hope ; and S. Chemnitzii Ad., from the Philippines, which was 

 figured by H. and A. Adams, 1858, and is considered as the type of 

 the genus. 



The following extract from a letter from Dr. Dall, under the date 

 of April 23d, explains the apparent confusion in the names which 

 have been applied to the type : 



" Gray's Separatista was founded on Turbo separatista of Chemn. 

 (x, figs. 1589-90), which was named S. chemnitzii by Adams (1850), 

 who adds a second species S. Grayi. Gray (P. Z. S,, 1847, p. 136) 

 cites Turbo helicinus Gmel., as a name for the former, but this was 

 a lapsus penncB for T. hellcoides Gmelin, who had, however, another 

 T. hellcoides, so that this one will retain the name of [Turbo) separa- 

 tista applied to it by Dillwyn (1817), to which Adams' name will fall 

 in synonymy." 



As nothing is known of the operculum or soft parts, the true posi- 

 tion is very doubtful. H. and A. Adams placed it in the subfamily 

 Rapaninse ; Fischer, as a questionable subgenus of Trichotropis, but 

 Mr. Dall, who states that he has examined the type in the British 

 Museum, placed it in the family ? Adeorbid^. He constituted a 

 new section Haloceras^ for Separatista cingulata (V.) Dall, the 

 young or immature form of which was described by Prof. Verrill as 

 Githna cingulata. The family Adeorbidaj can, however, only be 

 applicable to the genus Adeorbis and related forms, whose true posi- 

 tion is undeterminable until the odontophore of the type, subcarin- 

 atics, can be studied. 



Vitrinella C. B. Adams, 1850. Type, V. helicoidea C. B. Adams. Jamaica. 



Plate XXIII. figs. 9, 9a. 



" Shell turbiniform, vitreous, minute, with a large orbicular aper- 

 ture, either umbilicated or with the umbilical region deeply and 

 widely indented." 



iBull. Mus. Comp. Zool., xviii, p. 277, 1889. 



