308 TROCHIDA. 
subumbilicated, the umbilical region callous. Operculum flat- 
tened, with a depressed marginal line. East Indies. J. triuwm- 
phans, Phil. (Ixxx, 26). 
UVANILLA, Gray. Shell trochiform, conical, with moderately 
elevated spire; base concave, not umbilicated ; whorls flattened, 
rugose, spinously fringed. Operculum with two convex ribs, 
one nearly parallel to the margin, the other arcuated, subcentral. 
5 sp. Australian seas. I. fimbriata, Lam. (1xxx, 30). 
PACHYPOMA, Gray. Like Uvanilla, but base of the shell more 
concave. Operculum oval, subquadrangular, externally convex. 
7 sp. West Indies, Brazil. JI. celata, Chemn. (1xxx, 31), 
LITHOPOMA, Gray. Shell turbinated, not umbilicated, spire 
moderate, whorls with oblique longitudinal ribs and nodules ; 
inner lip concave, subtruncated in front, and with a longitudinal 
shallow channel. Operculum oval, thick, granulous externally, 
and flattened at the margins. West Indies. /. ¢uber, Linn. 
(Ixxx, 82.) 
POMAULAX, Gray. Shell trochiform, elevated conic, angulated 
and nodose at the periphery, obliquely ribbed, not umbilicated ; 
inner lip arcuated, with a wide callus, which is channeled, ante- 
riorly truncated. Operculum with three radiating ribs and 
perforated axis. Tsp. North Pacific, America and Japan. J. 
undosa, Wood (1xxx, 33). 
cookIA, Lesson. Shell turbinated, not umbilicated ; whorls 
nodulous ; columellar lip with a wide flattened callus and spiral 
shallow excavation. Operculum oval, flat, smooth, with a large 
subspiral, submarginal rib. New Zealand. J. Cookit, Chemn. 
(Ixxx, 34). 
BOLMA, Risso. (Tubicanthus, Swn.) Shell turbinated, not 
umbilicated, rugose or tuberculated, with deep suture; aperture 
round; inner lip wide, callous, concave. Operculum with a 
subcentral tubercle and spiral rib. 3 sp. Mediterranean Sea, 
China, Japan. J. rugosa, Linn. (1xxx, 35). 
Famity TROCHIDA. 
Shell usually conical, with flattened hege, nacreous inside. 
Operculum corneous, multispiral. 
Animal like that of Turbinide (p. 304). Differs from that 
family in its conical shell (usually) and its operculum ; that of 
Turbinide being calcareous and paucispiral. Dentition (xii, 46). 
DELPHINULA, Lam. 
Etym.—Diminutive of Delphinus, a dolphin. 
Syn.—Anegaria, Bolten. 
Distr.—20 sp. Eastern tropical seas. D. melacantha (xxx, 
36). Fossil. Jurassic—. - 
Shell orbicular, depressed; whorls few, angulated, rugose, or 
