1906.] NATURAL SCIENCES OF PHILADELPHIA. 169 



marked with growth-wrinkles, and shows some striae at right angles 

 to them. 



The radula (fig. 30) is normal for Goniobasis. The central tooth 

 has 4, 1, 4 denticles, the inner lateral 2, 1, 4, inner uncinus 7, outer 

 about 20 denticles. An inner uncinus in profile is drawn on the ex- 

 treme right side (fig. 31), to show the length of the denticles, which 

 are foreshortened in fig. 30. 



G. comalensis is dimorphic, like G. virginica and many other species. 

 At New Braunfels the smooth form described as typical predominates, 

 but there are also some individuals with numerous acute spiral ridges, 

 about fifteen on the last whorl, but often fewer by suppression of those 

 just below the periphery. 



At San Marcos only the smooth phase was found, in several hundred 

 specimens taken. 



A series of 12 labelled "Bexar county," received from A. G. 

 Wetherby, consists wholly of multistriate shells, which moreover, 

 although collected alive, are of a whitish or livid whitish tint, in this 

 respect approaching the Mexican pluristriatus. The largest of this 

 lot is 23.5 mm. long, 9.3 wide, exceeding in size any seen from Comal 

 or Hays counties. These are part of the lot collected by Mr. G. W. 

 Marmock, of Bexar coimty, and commented on by Wetherby in the 

 American Naturalist for 1878. The "variety marmocki" mentioned 

 by him, but without a word of definition, may have been the smooth 

 form of the species, but there is nothing to indicate this either in 

 Wetherby's note or the set of shells he sent to Tryon.^^ 



P'orm fontinalis, nov. Figs. 32-35. 



In a small spring in the pleasure garden near New Braunfels, one of 

 the fountains of Comal creek, we found only very small shells, the largest 

 7 to 8.3 mm. long, 4.3 to 4.7 mm. wide, and of a markedly short, conic 

 shape. The old ones are much eroded, and none are of the multi- 

 striate phase. This race inhabits only the springs and the rapid streams 

 from them for a short distance down. 



In another, much larger spring, and the stream from it for about 

 fifty yards down, the shells are also dwarfs, though somewhat larger 

 than those from the smaller spring. 



These springs flow out of the limestone rock, the water being beauti- 

 fully clear. It is not cold, being perceptibly warmer than the river 

 at the time of our visit, about the middle of April. There is very little 

 vegetation upon the rocks, and the small size of the snails may be due 



" Mr. Wetherby also mentions that "Helix photus Pfr." was collected by Mr. 

 Marmock. This name may be an error for H. tholus W. G. B. 



