Cyclostrema, Adeorhis^ VUrinella, and related genera. 99 



figured, is also an open question. Tryon's copies of Sowerby's fig- 

 ures do not agree perfectly with the figure in Gen, Rec, Moll,, and I 

 am unable to consult the original ones. 



The numerous small, rather thin, nearly smooth species from deep- 

 water which have been referred to Cyclostrema by several authors, 

 belong to several quite distinct genera. These have few convex 

 whorls, forming a moderately elevated spire ; the aperture circular, 

 not modified, as in affine Verrill =. proxima Tryon, or nearly circu- 

 lar and modified on the body-whorl, as in Dalli Verrill ; the 

 peritreme simple, entire, or more or less modified ; and the umbilicus 

 deep, but varying from one of moderate size to a scarcely percepti- 

 ble chink. 



Much careful study of the other numerous and varied forms, which 

 have also been erroneously referred to the genus, is necessary before 

 their true position can be determined. 



The family name Cyclostrematidae, constituted by Fischer, should 

 now be restricted to forms like the true G. cancellata Marryatt, and 

 perhaps may prove to be closely related to, or synonymous with, 

 Liotiinae (Adams and Chenu), Liotiidte (Tryon), or Delphinulida^ 

 (Fischer and Dall). 



The following extract from a letter from Dr. Dall, of the U. S. 

 National Museum, under the date of April 14th, shows the possible 

 relation of the genus, 



" I had never looked up Marryatt's original figures before, but 

 took this occasion for doing so. What he had was, it seems to me, a 

 Solariorhis (as I have been calling them) very much like some I 

 have been describing from the southern Miocene and Pliocene," etc. 



List of species belonging to the marine fauna of eastern America 

 which have been referred to Cyclostrema: 



Cyclostrema cancellata Marryatt, C. Schrammii Fischer, C. 

 Beauii (Fischer) Tryon = C. hicarinatum Guppy, C. angulata A. 

 Adams, C. Dalli Verrill {i\on C. fulgidum (Jeffreys, 1883) Dall), 

 and variety ornatuni Verrill, G. cingulatum Verrill = C. Verrilli 

 Tryon, G. affine Verrill = G. proxima Tryon {non G. trochoides 

 (Jeffreys MSS.) Sars.), G. diaphanum Verrill, G. valvatoides 

 Jeffreys, G. [Granigyra) limata Dall, G. txirhinum Dall, G. pom- 

 pholyx Dall, G cistronium Dall, C. gramdam Dall, G cancellatum 

 (Jeffreys) Dall {non Marryatt), G. tuberculosa {di^Ovhig^wy) Tryon, G 

 ".xcavata Watson = G. subexcavata Tryon, G diaphana (d'Orb.) 

 Poulsen i^ion Verrill). 



