MUSEUM OF COMPAUATIVE ZOOLOGY, 387 



round elevation on tlie inner side. It is thinner here than elsewhere, and 

 weathered operciila have always a central perforation. 



The minute varie^'ated Liotia {Arenc) miniata of the West Indies has a 

 similar operculum, as does A. tricarinata Stearns. L. liriareus Dall has an 

 operculum like that described by Arthur Adams, almost wholly horny, exter- 

 nally hispid, with a row of beady <,n'anules ou each whorl of the operculum. 

 In Liotia Bairdii the operculum seems to want even the granules, and to be 

 wholly horny. 



The sculpture is of two kinds; one, a fine shap^eenin^^ which generally covers 

 the whole surface and is only visible under a lens; it seems to be invariable 

 in the same species. The other sculpture consists of spiral ridges, or of scales, 

 spines, knobs, etc., which are very inconstant and not characteri.stic even of 

 the species in some cases. An examination of the dentition shows it closely 

 related to that of Belphinula, as might have been expected. 



The umbilicus varies from barely pervious (L. Riisii Dkr., etc.) to nearly 

 plane in the genus, and from perforate to wide in different individuals of the 

 same species, much as with some of the small Gibbulas. The elevation of the 

 spire often differs considerably in different specimens of the same species, and 

 the color markings are admitted on all sides to be as variable as they are bright 

 and elegant. 



The species of our southern coast and the Antilles appear to be as fol- 

 lows : — 



Liotia, Section Arene. 



Liotia Briareus Dall. Liotia cruentata Miihlf. 



Liotia Bairdii Dall. Liotia variabilis Dall. 



Liotia Riisii Dunker. Liotia tricarinata Stearns. 

 Liotia miniata Dall. 



Subgenus Lippistes. 

 Lippistes acrilla Dall. Lippistes amabilis Dall. 



Subgenus Laxispira. 

 Laxispira nitida Verrill. 



" Circulus" formosissimus Brugnone of tlie Mediterranean is also a Lippistes, 

 allied to L. acrilla. 



" Delpldnula " inherculosa Orbigny (tuherculata on the plate, which was pub- 

 lished first, Trochus Schrammi of Fischer according to the Beau catalogue) is 

 almost certainly a Fossarus. Cyclostrema Schrammi Fischer may perhaps 

 prove to be an. extremely young Lippistes. 



