Cyclostrema^ Adeorbis, Vitrinella, a9id related genera. 107 



teras, N. C, represented by Fi helicoidea C. B. Adams, V. Tryoni 

 Bush, V. diaphana (d'Orb.), and Y. carinata (d'Orb.) 



As the family names Cyclostrematidae and Adeorbidae, if used at all, 

 are applicable to other relations, I introduce Vitrinellidae to distin- 

 guish this group and extend it to include all small, more or less hya- 

 line, non-nacreous species, varying in form from those having a low, 

 little raised spire and large umbilicus, like Circulus, to the higher 

 spired, smaller umbilicated species, like Zissosjnra, and those with 

 closed umbilicus, like Tharsiella. Taking the form of the umbilicus, 

 the aperture, and peritreme, as the principal distinguishing charac- 

 ters of the several genera, such as : 



Deljihinoidea Brown, 1827, Vitrinella C, B. Adams, 1850, Circu- 

 lus JeflPreys, 1865, Ganesa Jeffreys, 1883, Granigyra Dall, 1889, 

 Tharsiella Bush, 1897, Lissosjnra Bush, 1897, Leptogyra Bush, 1897. 



The correctness of such a grouping depends entirely on the 

 future study of the opercula, animals, and odontophores. 



List of species belonging to the marine fauna of eastern America 

 which have been referred to Vitrmella : 



Vintrinella hyalina C. B. Adams, Y. interrupta C. B. Adams, Y. 

 megastoma C. B. Adams, Y. tincta C. B. Adams, Y. helicoidea C. 

 B. Adams, Y. striata (d'Orbigny) Tryon, Y. anomala (d'Orbigny) 

 Tryon, Y. [Ep>iscynia ?) middcarinata (Stimpson MSS.) Dall. 



Cynisca H. and A. Ad., 1858. Type, C. granulata A. Ad. Philippiues. 



" Shell depressly turbinate ; umbilicus wide and deep, perspective, 

 surrounded by a spiral callus ; whorls with transverse, granular 

 ribs ; aperture circular ; inner lip straight, outer lip thickened. Urate 

 within, continued posteriorly on the penultimate whorl beyond the 

 inner lip." Gen. Rec. Moll., p. 406, 1858. 



Type, C. granulata^ not figured. 



In Ann. and Mag. Nat. Hist., vol. viii, 1861, A. Adams, under 

 the genus Cynisca, stated : " In our Gen. Rec. Moll., vol. i, p. 406, 

 my brother and myself proposed a subgenus of Cyclostrema under 

 the name Cynisca. This was founded on a shell in Mr. Cumings' 

 collection, which I described as Cyclostrema granulata (P. Z. S., 

 1853). The great peculiarity consists in the aperture, which is 

 something like that of Stoastoma, the inner lip being straight and 

 the outer lip being continued posteriorly on the penultimate whorl 

 beyond the inner lip." 



He added two species, Delphimda australis Kiener, which has 

 more recently been referred to the subgenus Liotina Munier-Chal- 



