226 



Valtata areijifera, Trans. Amer. Philos. Soc. vol. 4, N. S. In the 

 Wissihickon and other streams of water in the vicinity of Philadelphia 

 is the larvae of a common insect belonging to the Ltnnsean genus Phry- 

 ganea, which constructs a spiral follicle precisely similar to the descrip- 

 tion and figure above referred to, excepting, of course, that it is destitute 

 of operculum, which the author says, in two of his specimens was 

 " sufficiently perfect to exhibit a striated horny structure." The oper- 

 culum seems to have been imperfect in both specimens, and we fear that 

 a mistake may have been made, and that the V. arenifera, is in reality 

 only the follicle of a larva and not the production of a molluscous ani- 

 mal. It would be easy to make the necessary comparison, as thfe 

 follicle is well known to most of the conchologists of that city. 



Caracolla helicoides. ibid, is a variety a of Helix palliata, S., H. 

 denotata, Fer. 



Helix carolinensis, ibid, corresponds by description and figures with 

 H. appressa, S., var. a. 



Melania tuberculata, ibid, is a variety of M. stygia, S. 



MeIiAnia elongata, ibid, seems very closely related to M. elevata, S., 

 and may probably prove to be the same. 



[Amer.'Conch.'p. vii.]* 



DoNAX VARIABILIS, nob. Joum. Acad. Nat. JSci., vol. 2, 

 p. 305. PI. 61,/. 1. 



DoNAX FOSSOR, iiol. Jotim. Acad. Nat. Sci., vol. 2, p. 306. 

 m. 61, /. 2. 



Cyrena CAROLINENSIS, Base. Say. — Nicholson's Encyclopedia, 

 {Sd American ed^'t ion,') article Conchology. 



Ohs. It inhabits Mobile Bay, in the vicinity of Mobile, Ala- 

 bama, and occurs fossil in the Newer Pliocene of North Carolina, 

 near Newbern.— ED.f PI. 62. 



Venus alveata. — Desc. Shell ventricose ; valves very thick, 

 subtriangular, cordate, with eight remarkably thick, very promi- 

 nent, much recurved, transverse approximate ribs, of an imiform 

 thickness throughout, terminating abruptly at their anterior slope 

 which is much impressed ; lunula cordate, included by an im- 

 pressed line. 



* [No date is given for this part. It was printed after Mr. Say's deatli, 

 which occurred in Sept., 1833. — Ed.] 

 t [T. A. Conrad.] 



