216 ONUSTIDA. 
admirably adapted to to the nature of the floor on which they 
live, which is usually composed of the debris of dead shells. 
Onustus, H. and A. Adams. 
Syn.—Halipheebus and Tugurium, Fischer. 
Distr.Several sp. repeal East and West Indies. 0. 
solaris, Linn. (1xvi, 31,32). Fossil. Devonian—. 
Shell conical, trochiform , depressed, widely and profoundly 
umbilicated ; periphery of the whorls fringed with regularly 
disposed tubular spines or slight projections; pieces of small 
shells agglutinated upon the whorls at the sutures, where they 
are attached as growth continues. 
Evurrocuus, Whitfield, 1882. 
Distr.—E. concava, Hall. Carb.; Ind., Ils. 
Shell conical above, flat or Goritave beneath, and broadly and 
deeply umbilicated ; aperture very oblique, and the outer angle 
of volutions strongly carinated or expanded ; surface ornamen- 
tation unlike on the upper and lower surfaces. 
Differs from the umbilicated forms of Trochide in not forming 
a columella; the lower or basal surface sloping gradually and 
smoothly into, and forming the sides of, the umbilicus, giving an 
obliquely elliptical section to the volution. 
XENOPHORA, Fischer de Wald. 
Syn.—Phorus, Montf. Pseudophorus, Meek. 
Distr.—Several sp. Tropical. X. conchyliophora, Born 
(Ixvi, 33). Fossil. Devonian—. 
Shell conical, trochiform, whorls flattened, carrying shells, 
madrepores and stones, miscellaneously arranged and attached 
anywhere upon the exterior surface, so as to completely disguise 
the dorsal aspect of the shell; lower surface free of extraneous 
agglutinations; umbilicus narrow, sometimes covered by the 
inner lip. 
The “carriers” inhabit deep water, and are most numerous in 
the Java and China Seas. Each species appears to have its own 
peculiar method of collecting the fragments of shells and stones 
which cover the ground where it lives, and each cements to the 
outside of the shell its particular kind of materials. The adven- 
titious pieces of shell are so disposed as not to curve downwards 
beyond the edge of the shell, so as to impede the progress of the 
animal, but are usually placed with their coucave sides upper- 
most, and the purpose of this structure is evidently concealment 
of the true nature of the animal, either for attack or defense, or 
perhaps for both occasions ; as when tricked out with shells and 
stones it may well be mistaken for a refuse-heap. 
ENDOPTYGMA, Gabb, 1877. Differs from Xenophora in having 
