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- 
sary, and numerous generic and subgeneric names have been applied 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 Rea? species as subfamilies Zurri- 
tinae and Mangiliinae respectively. 
The following groups are recognizable among the species of Zurritinae treated 
of in this memoir: 
Turris s. s., large fusiform strongly sculptured shells, 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. 
Surcuta H. and A. Adams, 1853 (Surgula Weinkauff, 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 javanus Linné. 
Dritia Gray, 1838. 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. 
Gremmuta Weinkauf, 1876. Shell resembling Drillia, but with a thin 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 Plewrotoma gemmata 
Hinds. Hemipleurotoma Cossmann, 1889, is believed to be synonymous. 
Pseupotoma Bellardi, 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 riblets; operculum wide, ovate, with 
apical nucleus. Type Pleurotoma intorta Brocchi. 
Levcosyrinx Dall, 1889. Shell moderately large, thin, white, or pale, with im- 
pervious axis, the sculpture chiefly of delicate spiral threading with feeble axial 
riblets at the shoulder ; anal fasciole wide, shallow, next the suture; canal mod- 
erately long, distally flaring; the pillar thick, anteriorly obliquely truncate ; oper- 
