256 bulletin: museum of comparative zoology. 



This family probably contains more species than any other group of Gastropods of 

 the same rank. Their variations are such that subdivision is imperatively neces- 

 sarv, and numerous generic and subgeneric names have been apphed to both recent 

 and fossil groups. The work has been done in a more or less superficial mauner, 

 and the result is that the nomenclature of the group stands in great need of revision 

 by some one who will go into the matter with thoroughness, patience, and care. 

 I have felt unable at present to give the time needed, and therefore feel obliged 

 to state that the subdivisions adopted in this memoir are but provisionally and 

 tentatively used. The final systematic arrangement of the family cannot be had 

 until the anatomy and dentition are better known. There is little doubt, how- 

 ever, that the subdivisions will prove fully as numerous as they are at present, 

 though many of the old ones will have to be rejected for various reasons. 



At present the most convenient way of dividing the family seems to be by sepa- 

 rating the two groups of operculate and inoperculate species as subfamilies Turri- 

 tinae and Ma?igiliinae respectively. 



The following groups are recognizable among the species of Turritinae treated 

 of in this memoir: 



TtJKRis s. s., large fusiform strongly sculptured sliells, with a long spire, a 

 long straight canal, the outer lip not thickened or reflected, the anal sulcus not 

 close to the suture, and the operculum claw-shaped or narrowly oval, with an 

 apical nucleus. 



SuBCULA H. and A. Adams, 1853 {Surgula WeinkaufT, 1876). Shells simi- 

 lar, but with the body more robust, the canal shorter and often more or less 

 curved, the sinus close to the suture. Type Murex javatius Linn^. 



Drillia Gray, 1833. Shells relatively smaller, solid, mostly strongly sculp- 

 tured, with a conspicuous sulcus anteriorly and another near the suture in a 

 thickened and produced outer lip ; a callous inner lip and short canal. Type 

 D. umbilicata Gray. 



Gemmcla Weinkauf, 1876. Shell resembling Drillia, but with a tbin and sim- 

 ple outer lip without an anterior sulcus, and the pillar lip usually simple, hardly 

 callous, the sculpture most emphasized in a spiral direction, often with a promi- 

 nent beaded keel at or in front of the anal fasciole. Type Pleurotoma gemmata 

 Hinds. Hemiplcurotoma Cossmann, 1889, is believed to be synonymous. 



PsEUDOTOMA Bcllardi, 1875. Shell ovate, fusiform, short, stout ; spire about the 

 length of the aperture, columella straight, very short, axis impervious, canal very 

 short and wide; anal sulcus wide, moderately deep, close to the suture; spiral 

 sculpture feeble, axial of moderately strong riblcts ; operculum wide, ovate, with 

 apical nucleus. Type Pleurotoma intorta Brocchi. 



Leucosyrinx Dall, 1889. Shell moderately large, thin, white, or pale, with im- 

 pervious axis, the sculpture chiefly of delicate spiral threading with feeble axial 

 riblcts at the shoulder ; anal fasciole wide, shallow, next the suture ; canal mod- 

 erately long, distally flaring ; the pillar thick, anteriorly obliquely truncate ; oper- 



