240 PKOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



to be " Venus rimularis, Lam. (as V. virginea, L.)." Further, in the text 

 he remarks that " Eomer proposed Hemitapes for a group typified by 

 V. rimularis, Lamarck." 



I cannot understand why Dr. Dall made the positive statement that 

 V. rimularis was the type of Hemitapes, for that name is merely given 

 as a synonym of the first species on Romer's list, and nothing is said 

 by Eomer about a type. As already pointed out in the case of Marcia, 

 it cannot be maintained that an author determines a type when he 

 erroneously assumes or supposes a type to have been indicated by 

 a previous author. Further, if an error of this kind could be accepted 

 as determinative, then Stoliczka's mistaken belief that V. pinguis was 

 the type would have priority of Dr. Dall's mistake. 



At the same time, as there is no reason why V. rimularis, Lam., 

 should not be taken as the type of Hemitapes, and as I do not desire 

 to increase the confusion by selecting any other species, I prefer to 

 take the species which Dr. Dall imagined to be the type, and in order 

 to establish it I merely observe that in my judgment V. rimularis is 

 now for the first time properly and definitely determined as the type 

 of Hemitapes. 



With regard to the second section of Romer's Hemitapes (the pinguis 

 group), I have already shown that it should bear the name of Marcia. 

 I think few conchologists will agree with Dr. Dall that this group 

 should be placed in the genus Oomphina ; at the same time, there are 

 some other differences between it and the rimularis group besides the 

 smoothness of the shell; these are the following: — 



The escutcheon of Marcia is never defined. The lunule is impressed, 

 but the lunular border of each valve has an outward bulge above the 

 anterior tooth. The hinge-teeth are more widely divergent, the right 

 anterior being parallel to the general trend of the lunular border, not 

 oblique to it ; the right posterior is broad and bifid. In the left valve 

 the median and anterior teeth are of nearly the same thickness, and 

 both are grooved. 



These differences are hardly of more than sectional or subgeneric 

 value, and H variabilis (Phil.) {= H. marmorata, auctorum) seems to 

 be a kind of connecting link between the two groups, so that, as 

 already stated, I regard Hemitapes as merely a subdivision of Marcia, 

 and am consequently in accord with Romer in this matter. 



4. Kateltsia, Eomer, 1857. 



This name was proposed and published in the same year as the 

 Marcia of Messrs. Adams, but three months later. ^ Romer's ideas of 

 nomenclature at this time were peculiar ; he divided the Linnaean 

 Venus into a number of ' subgenera,' which we should now rank as 

 genera, and these subgenera he divided into '■ families,' which we 

 should now call sections. In this way he proposed a ' subgenus ' 

 Murcia, which he again divided into five families, the last of which he 

 named Katelysia. The work consists of an introduction, a scheme or 

 tabular view, and a list of species. No types are indicated for any 



1 Krit. Untersuchimg der Arten des Moll. Venus, Cassel, 1857. 



