306 AilLKKAN JOUKNAL. 



NOTES ON SOME NEW FORMS OF TERRESTRIAL AND 

 FLUVIATILE MOLLUSCA FOUND IN TRINIDAD. 



BY R. J. LECHMERE GUPPY. 



Mr. Thomas Bland communicated in 1868, to the American 

 Journal of Conchology (vol. iv, pt. 4), a memoir on the land 

 shells of Trinidad and other islands. Since the discoveries 

 referred to by Mr. Bland in that paper, I have detected some 

 additional species, two of which appear to belong to genera pre- 

 viously unknown. The descriptions of some of these shells 

 have been published in the Proceedings of the Scientific Associa- 

 tion of Trinidad for December, 1868 ; but further notice of 

 them, and especially of the new genus Autonoe, may be of inter- 

 est. Other species are now herein described for the first time. 



The genus Autonoe was created by me, in the publication above 

 mentioned, for a shell which bears a certain resemblance to a 

 Melampus, but differs from that genus, especially in its texture, 

 which resembles that of a land-shell. 



I append the following technical diagnosis of the genus. 



AUTONOE, n. gen. Plate 17, Fig. 1. 



Testa tenuis, cornea, ovato-obconoidalis ; anfr. ultimus com- 

 pressus, superne paulum angulatus ; spira brevis, conoidalis ; 

 apertura elongata, angusta, ante paulum dilatata; peristoma 

 simplex; columella valde torta, arcuata, plicis fortibus munita. 



Autonoe riparia, the species on which the genus is founded, is 

 a nearly smooth ovate-obconoidal shell of about five whorls, 

 whitish under a straw-colored epidermis. The aperture is nearly 

 the length of the shell, widened below, the inner lip covered with 

 a callus and furnished with a strong plait. The columella is 

 strongly twisted. 



Length 10 mill., breadth, 6 mill. 



I found one example only on Mayaro Point, amongst the 

 bushes, some ten or twelve feet above the highest limit reached 

 by the waves of the sea, a habitat, it will be noticed, very simi- 

 lar to that of the Auriculidce. 



