GUPPY : MOLLUSCA OF TRINIDAD. 221 



larger size, which is undistinguishable from Streptaxis glaber 

 Pf. I should be inclined also to add S. deplanchei Drouet to 

 the synonymy. 



28. Simpulopsis corrugata Guppy. 

 'Jom-n. Conch.,' 1878, p. 323, pi. x., f. 3. 

 Crosse, ' Journ. de Conch.,' 1890, p. 46, No. 30. 



A greenish-hyaline membranaceous shell, wrinkled or 

 corrugated. Height 10 mill., diameter 8 mill. 



I am not quite certain that this is a valid name. Want of 

 means of comparison with named forms sometimes causes the 

 description of a local race as a different species. 



29. Succinea candeana Lea. 

 Succinea approximans Crosse, I.e., p. 47, No. 31. 

 6". margarita Crosse, I.e., p. 47, No. 32. 



S. ciivieri Guilding. 



I cannot find satisfactory marks of distinction between the 

 Succineas {senfu strictiore) found in the different islands of the 

 Antilles, nor can I make two races of the Trinidad forms. 

 They vary indeed in proportions, but this, I think, is due only 

 to local conditions. There may be some difficulty in selecting 

 the right appellation, and in 1877 I pitched upon that given 

 here as the preferable one according to my lights. I cannot 

 separate the shells denominated — ciivieri, margarita, approxi- 

 7/ia?is, etc., by any decided or definite and permanent character. 



30. Omalonyx felinus Guppy. 

 'Journ. Conch.,' 1878, p. 324, pi. x., f 2. 



Crosse, 'Journ. de Conch.,' 1890, p. 48, No. 33, pi. ii., f. 4. 



A similar remark applies to this as to the Simpulopsis. So 

 far as concerns the shell I see no difference that could be 

 regarded as specific between our specimens and those from 

 Guadelupe, Guiana, and Brazil, and these latter are all referred 

 to OmaloTiyx unguis Fer. ; but the soft parts of our Omalonyx 



