52 Qttarteiiy Journal of Conchology. 



The species considered as typical by Guilding was the C. costata 

 (Brachypus), Guilding, from Barbadoes, an elongated many-whorled 

 shell, with an entire, nearly circular aperture, and truncated at the 

 apex', and the genus as defined by Pfeifier was distinguished from 

 Pu2)a by the peristome being contiauous and detached, or nearly so, 

 and from Clausilia, which some of the species somewhat resemble in 

 shape, by the absence of the clausilium. In his first edition (Men. 

 Heliceorum IT., pp. 368—386), published in 1848, Pfeiffer enumerates 

 50 species, chiefly from Cuba and Jamaica, with a few from the other 

 West India Islands and from Mexico and Texas. 



To the genus so constituted species continued to be added from 

 time to time, but the geographical area in which the genus was 

 known was scarcely, if at all, extended. The majority of the new 

 species were found by Adams and Clutty in Jamaica, and by 

 Gundlach in Cuba. The numbers increased so much, that in 1868 

 223 species were catalogued. 



In the meantime various subgeneric divisions were proposed, 

 some of them destined to stand either as genera or subgenera, but 

 others merely artificial ; but it was not till the animals, as well as 

 the shells, had been studied, that any certain basis was obtained for 

 alterations in the genus. 



The anatomy of Cylindrella has been studied chiefly by Messrs. 

 Bland, Crosse, and Fischer, and the result has been briefly this : — 



1. All the large Mexican species of the type of C grandis 

 (Pfeiffer) have parallel rows of teeth of the usual type in Helicidse, and 

 a solid horny jaw, with some fine strife. These form the genus 

 Eucalodium (Crosse and Fischer), and are true Helicidse. The 

 species are confined^to Mexico and Guatemala. 



2. The rather small thick species, not truncated at the apex, and 

 of a cretaceous aspect, such as G. Pilocerei (Pfeiflfer) have also 

 horizontal rows of teeth, and the jaw is thin and not striated. 

 These are also true Helicidse, and for them v. Martens' sub-genus 

 Holospira has been raised into a genus, after the exclusion of certain 

 species, such as Ainostoma, which are true Cylindrelke. 



3. The anomalous shell from Lower California, first described as 

 Clausilia Taylori, and afterwards called a Cylindrella, has been shown 

 to have horizontal rows of teeth, and a ribbed jaw. It forms at 

 present the only known species of the genus Berendtia (Crosse and 

 Fischer). 



4. The remaining sj)ecies are all distinguished by teeth of a 

 peculiar palmate foi-m, arranged obliquely on each side of the median 

 line, and by a very thin jaw with numerous transverse ribs, of 

 which the two median ones enclose a V shaped space. The same 

 characters are found in Macroceraraus, a genus conchologically also 

 very similar to Cylindrella. Messrs. Crosse and Fischer have there- 

 fore formed out of these genera the family Cylindrellidce. 



They also express an opinion that there will be reason to separate 

 as a distinct genus the section Lia (Albers). In this I quite concur. 

 The species of Lia are distinguished from the rest of the Cylindrellida', 



