42 



LAND AND FRKSII-'WATER SHELLS OF N. A. fPART IL 



Fig. 53. 



I^iEBinaea attenuata, Say. — Sliell elongate turreted, somewhat 



translucent ; spire slender, attenuated, acute ; whirls six or seven, with 



but a very slight convexity ; wrinkles more distinct towaids 



the aperture ; body whirl, measured at the back, obviously 



less than half tlie total length. Length one inch. 



Inhabits Mexico. 



This species abounds in ditches and ponds in the vicinity 

 of the ca^iital. It is more nearly related to L, reflcxus, nob., 

 than to any other known species of North America ; but it is 

 only necessary to compare the two in order to perceive a wide 

 difference between them. The present is smaller and propor- 

 tionally rhore slender, and the spire is more attenuated. (^Say.) 

 Limnxa atteniiata, Bay, New Harm. Diss. II, 244 (1829) ; 

 Bunnfa's ed. 148 ; Descr. 23.— DeKay, N. Y. Moll. 75 

 (1843).— Haldejiax, Mon. 28, pi. ix, f. 1-5 (1842).— 

 KiJSTER (Li?nnseiis), Chemn. ed. 2, 39, pi. vii, f. 8. 

 Limnaeus fnibulatiis, Dcnker in Kuster, Ch. ed. 2, 24, pi. iv, f. 24. 



Figure 53 is drawn from an authentic specimen of Mr. Say. 

 His description is given above. 



In describing the habitat of Planorhis tenuis, in Chemnitz, 

 ed. 2, Limnseus subulafus is mentioned as common among graves 

 near Mexico. There is also a L. subu'lata, Kiclix, mentioned in 

 Dupuy's MoUusques de la France, p. 463. But the species re- 

 ferred to is, I suppose, tlie one described in Kiister's ed. 2 of 

 Chemnitz, Limnasa, p. 24, pi. iv, f. 24. As the last livraison de- 

 voted to Limnaia, which has reached this country, contains only 

 a portion of the description of the species, I cannot say what 

 locality is given by Kuster for the shell. The figure corresponds 

 with Limnsea attenaata, Say. It is copied in Figure 54. A 

 translation of the description here follows : — 



Shell imperforate, subulate-turreted, solid, striated, reddish horn-color; 

 spire elongate, subulate, acu- 

 minate ; whirls seven, flattened ; 

 aperture semioval, yellowish- 

 red, sanguineous at the base ; 

 peristome straight, sharp, ob- 

 lique, with a distinct colnmellar 

 fold. (JJunker.) 



Since writing the above 

 the succeeding part of Chem- 

 nitz, ed. 2, having arrived, i 



find the locality to be Mexico, at Zimapan and Lake 

 of Mexico. 



Fig. 54. 



Fig. 55. 



L. uttenuatn. 



L. srd/ulata. 



