OP CONCHOLOGY. 89 



that I fail in neither, in here presenting some criticisms upon the 

 monograph of Ilarginella, which was completed in 1865 ; for 

 mj sole object is to indicate what seem to me errors too impor- 

 tant to pass unquestioned, or to call attention to points which 

 need further investigation. 



And I would remark generally, that while the larger species 

 of 3Iarginella are for the most part as well defined in form and 

 marking as are the species of Cyp^'cea, the great number of 

 smaller species which have been brought to light in recent years 

 form groups which from want of positive distinctions of color 

 and pattern, and from the slightness of deviation in form, are 

 most perplexing to the student. For their proper delineation, 

 the highest style of art is required ;* for their distinction, both 

 back and front views are needed, and their proper characterization 

 should be based only upon fresh, bright and perfect individuals. 

 Mr. Reeve's plates of the smaller species often fail in all these 

 respects, while his descriptions are vague and insufficient. Hence 

 of the species which he has for the first time named, many must 

 remain doubtful, especially as in so many of them the habitat 

 is unknown. 



Referring to the species in the order of the monograph, I offer 

 the following notes : 



Sp, 6. 3Iarginella Petitii, Duval. The habitat of this species 

 is left in doubt by both Sowerby and Reeve, but it is known to 

 inhabit the coast of Senegambia, West Africa. 



Sp. 13. M. pyrum, Gron. The quoted synonym of Valuta 

 picta should have been referred to Dillwyn instead of Gmelin. 



Sp. 14. M. rosea, Lam. I believe that Senegal should be 

 omitted from the habitats of this species, although the authority 

 of both Kiener and Sowerby may be pleaded for it. The re- 

 maining localities given by Reeve, to-wit, — Cape of Good Hope 

 and Natal — are certainly correct, and, so far as I know, it is 

 limited to that region. 



Sp. 15. M. Netvcomhij Reeve. I see no reason why Reeve 

 should have considered this a doubtful species. It certainly has 

 very slight affinity to M. rosea, Lam. 



Sp. 17. M. vittata, Reeve. This species has no habitat 

 assigned. It was sent me many years ago by Mr. Cuming, as 

 from East Africa, and it has just enough relationship to M. 

 pyruni, Gron., to render that habitat probable. Sowerby 's 31. 

 mtermedia, not mentioned by Reeve, is closely allied. 



*Even in Kiener's beautiful plates the smaller species of Marginella 

 are very badly and imperfectly rendered. 



