1922] NATURAL SCIENCES OF PHILADELPHIA. 63 



is doubtless erroneous. However, Eutrochatella does have a larger 

 number of unicuspid marginals than does Ustronia, and in this 

 features agrees better with Priotrochatella. Its separation from 

 Excavata seems justifiable on the basis of the heavier sculpture of 

 the shell in this typical section. 



Genus VIANA. H. and A. Adams. Cuba. 



Viana H. and A. Adams (March, 1856). Type H. regina Morelet (1849). 



Cuba. 

 Hapata Gray (Nov., 1856). Type H. regina Morelet. 

 Rhynchocheila Shuttleworth (1878). Type H. regina Morelet. 



In this genus, through the kindness of Mr. J. B. Henderson, I 

 have been able to examine the type species 56 . Before receiving his 

 material, the laterals alone of V. regina subunguiculata (Poey) 

 were obtained by washing out dermestid feces from an old shell. 

 V. regina is figured (Plate VII, figs. 34, 35, 36). 



The paired centrals have no definite cusps, although there is a 

 rounded hook on the C-central. The R-central is shield-shaped with 

 two scallops on each side, a very well-marked triangular cusp, and a 

 rounded base. The A-central is proportionalely very large, while 

 the B and C centrals are much smaller, and appear to be rather 

 weak, as they are easily crushed in mounting the specimen, The 

 T-laterals are exceptionally large (.5 mm. in diameter) ; each is 

 fully as large as the whole central area (7 teeth). The stalk or 

 base is proportionately very short and stout, while the reflecteb 

 portion is semicircular (Plate VII, fig. 36 gives anterior view) and 

 very large. It is less dome-shaped than in Eutrochatella. The 

 accessory plate is small and, when united is almost completely 

 hidden by the T-lateral. The unicuspid marginals are more broad- 

 ly rounded at the tips than are those of Eutrochatella and the 

 inner, multicuspid ones are not as deeply cleft. 



In addition the shell-characters are peculiar. Especially note- 

 worthy is the definite sinus on the outer lip of the aperture of the 

 male. Altogether, it seems that the generic separation of this 

 group is justifiable on natural grounds. In addition, there is a 

 practical reason. Viana (and also its two synonyms) is prior to 

 Eutrochatella Fischer, and would become the generic name of the 

 entire group if the two were combined. The resemblance of Fischer's 

 term to the original, preoccupied name, Trochatella, and its wide 

 acceptance, would make this peculiarly unfortunate. 



56 2 alcoholic specimens; Cuba from collection of J. B. Henderson. 



