THE NAUTILUS. 69 



characters of the soft parts (the "caruncle" in front of the 

 branchial opening, and the inner lamina of the inner gills, 

 which is more or less free) sufficiently distinguish it from 

 Eurynia. In addition, there seems to be a difference, from 

 Eurynia, in the glochidia, which are suboval, with the mar- 

 gins rather regularly curved, not much higher than long, and 

 smaller in the two species of Carunculina, in which they are 

 known. In Eurynia, subgenus Micromya, the glochidia are 

 larger, distinctly higher than long, and nearly subspatulte, 

 with the anterior and posterior margins nearly straight. In 

 the typical Eurynia, the glochidia are subovate, but larger 

 and higher in proportion. 



I have given (1. c.) U. parvus Barnes as type of the sub- 

 genus, while Simpson (1900) names U. texasensis Lea. 

 However, when Simpson first published the subgenus (as 

 section, in : Baker, Bull. Chicago Ac. Sci. 3, 1898, p. 109, 

 misprinted as Corunculina^), he used it only for one species, 

 U. parvus, and this, consequently, is to be regarded as the type. 



(To lie continued.} 



PHYSA HETEROSTROPHA SAY" IN EUROPE. 



BY CAESAR R. BOETTGER. 



In the NAUTILUS, Vol. xxvii, No. 10, pp. 112-113, Mr. Fran- 

 kenberger states that all the Physas lately introduced into Cen- 

 tral Europe are not the European Physa acuta Drap. but the 

 North American Physa heterostropha Say. He believes that 

 Babor and Novak were the first to record this North American 

 shell in the waters of Central Europe. This is not the case. 

 In 1907 D. Geyer already mentioned (Jahreshefte des Vereins 

 fiir Vaterl. Naturkunde in Wiirttemberg, 1907, pp. 426) that 

 it is possible that the ancestor of our form is Physa heterostropha 

 Say. It may be that now and then Physa heterostropha Say is 

 introduced into Germany with American fishes and plants of 

 aquaristic commerce. But this must be very rare and the ex- 



