402 Report on t/u Mottusca of Long Island, N. )'.. 



thircU <T three-quarters; while, as before mentioned, specimens in all 

 Btagea of development occurred in June, though in a smaller total 



mi, til' r of indi\ itlnals. 



In \i.-w ..t' this tact it Beems difficult to answer satisfactorily, as 

 the questions proposed by Stimpson in his description of Gr. 

 1/ Idana (Proc. Bost. Soc. Nat. Hist.. L863, p. 249) with regard to 

 the period and course of development of our species of Ghmdlachia, 

 li may be remarked, however, that the septum is evidently formed at 

 an early period of the year, and probably not in the \\ inter, as other- 

 wise it is difficult to account for the fact thai all those found late 

 in the seasoD had the septum fully developed, while in June adults 

 and half-developed specimens occurred. 



A.bou1 one hundred specimens of the species have hitherto been 

 tumid. 



111. Limnea columella, Say. Coldspring, Huntington, East Mar- 

 ion, and ( Sreenport. I lommon. 



142. Limnea humUis, Say. Lloyd's Neck, Huntington, Center- 

 port, and i;i\ erhead. 



143. Zjimnea desidiosa, Say. Astoria and Huntington. 

 I 11. I'lii/sn lieterostropha, Say. Common. 



\;ir. Primeana, Tryon (Amer. J. Conch., Vol. 1st. p. 227). Hun- 

 t Lngton. 



I I"', Physa dongata, Say. Huntington and Centerport. Rare. 



1 In. Planorbis trivolvis, Say. Huntington, rare; Riverhead and 

 Montauk, common. 



117. Planorbis bicarinatus, Say. Huntington and Centerport. 

 < lommon. 



148. Planorbis armigerus, Say. Brooklyn (Ferguson), Ureenport, 

 and Shelter Island. 



149. Planorbis exacutus, Say. Greenport. Rare. 

 160. Planorbis parvus, Say. Common. 



151. Planorbis dilatatus, Gould. Huntington, Southold, Green- 

 port, ami Gardiner's Island. Rare. 



HelicidflBi 



152. Ffelix cellaria, Miiller. Astoria (Binuej and Bland). 



153. Helix arbor pu, Sa\. Common. 



