﻿EXOTIC UNIONIDJE. 259 



Palpi rather large, suboval, open nearly the whole length of posterior edge. Mantle 

 thin, thicker along the edge, and bordered with black. Branchial opening rather 

 large, with numerous, rather small, brownish papillae. Anal opening large, with 

 numerous small, brownish papillae. Super-anal opening large, bordered with black 

 and united below. Color of the mass whitish. 



Remarks. — A number of very much eroded specimens were obtained by Dr. Le 

 Conte in his late travels in Honduras, and one specimen only was obtained in alcohol. 

 In outline this species is near to suhangulatus, (nobis), and to Rowellii, (nobis), from 

 Chagres. It would be more likely to be confounded with the latter than any other 

 species I am acquainted with. It is of nearly the same color in the epidermis, but 

 may be distinguished by not being sulcate, in being more inequilateral and more 

 compressed. The older specimens have no rays, but the young ones have a few 

 obscure rays. None of the specimens had perfect beaks ; they were all too much 

 eroded to shew undulations, if any ever existed on them. This and Unio scamnatus, 

 More., are the only two species of the family Unionidm found by Dr. Le Conte in 

 Honduras. It is an interesting fact that scamnatus should inhabit Honduras as well 

 as Cuba, separated as the two habitats are by the Carribean Sea. The scamnatus was 

 found at Cumayagua. 



Unio Scamnatus. 



Unio Scamnatus, Morelet. Test. Nov., No. 1, p. 30. 



Unio Gundlachi, Dunker. Prof. Poey's letter. 



Soft parts. — Branchial uterus . No ova were found, either in the branchiae or 



abdominal sack of seven specimens received in alcohol. Branchiae large, curved 

 below, the inner one much the larger, free nearly the whole length of abdominal 

 sack. Palpi very small, angular, united only for a very short distance on the poste- 

 rior edge. Mantle thin, thickened on the margin where it is slightly colored. Bran- 

 chial opening large, with numerous small, brown papillae on the inner edges. Anal 

 opening rather large, with numerous very small papillae on the inner edges. Super- 

 anal opening small, edge with a delicate deep brown line. Color of the mass dirty 

 white. 



Remarks. — This well characterised sulcate species, first observed by the late Mr. 

 Morelet, of Geneva, has been, until lately, considered to be peculiar to Cuba, but 

 recently it has been found by J. L. Le Conte, M. D., in Honduras, at Cumayagua, 

 and to this intelligent naturalist I am indebted for a suite of different ages from that 

 habitat. It is remarkable that no other species of Unionidce has been found in the 

 West India Islands, and that this should inhabit both sides of the Carribean Sea. I 

 am a, ware that other species have been reported from other Islands, but I have doubts 

 of the authenticity of the statements. From time to time Prof. Poey, of Havana, 



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