378 POLYCERIDA. 
PLocaMopHorus, Ruppell and Leuckart, 1828. 
Syn.—Plocamoceros, Cuv., 1830. Plocamophorus, Gray, 1842. 
Peplidia, Lowe, 1842. Histiophorus, Pease, 1860. 
Distr.—10 sp. Red Sea, Australasia. P. ocellatus (xe, 5). 
Body limaciform. Mantle represented by a supracapital veil 
bearing tuberculate or branched appendages on the margin, and 
by two or three tubercular processes upon each side of the back. 
RKhinophores laminate. Oral tentacles flat. Branchiz few, non- 
retractile. Tail dorsally carinated. Odontophore with the 
spines near the middle bicuspid, none median in position, An 
incomplete buccal collar. 
Aiaizus, Loven, 1846. 
Disir.—3 sp. European coasts. 4. punctilucens, d’Orb. 
(xe, 6, 7). 
Body convex, covered with large tubercles. Mantle indis- 
tinct, represented by a supracapital veil, and by a tubercular 
ridge along each side. Rhinophores linear, smooth or hispid. 
Branchiz non-retractile. Odontophore with simple, curved, 
lateral spines; no central spine. An upper corneous jaw. 
Noroporis, Bergh, 1875. 
Distr.—N. citrina, Bergh. Rarotonga. 
Body limaciform (the back not distinct from the sides). 
Rhinophores smooth, retractile in cavities protected by valves. 
No buccal armature. Lingual teeth, none median, the lateral 
ones erect and hook-shaped.—BERGH. 
Creratosoma, Ad. and Reeve, 1848. 
Distr.—8 sp. Australasia and Canary Isles. C. cornigerum, 
Ads. and Reeve (xc, 8). 
Body elongate, prismatic, smooth, ending in a bluntly pointed 
tail; the dorsal surface passes into a post-branchial flesh protu- 
berance. Mantle obsolete. Rhinophores laminated. Branchie 
with the roots more or less coherent, placed in front of and par- 
tially around the tubular anus, with which they are retractile 
into a common, smoothly margined cavity. Odontophore with 
numerous rows of simple spines, none of which are central. A 
spinous buccal coilar. 
TREVELYANA, Kelaart, 1858. 
Syn.—Gymnodoris, Stimpson, 1855. Stenodoris, Pease, 1866. 
Distr.—l1 sp. Red Sea, Indian Ocean and Australasia. 7’. 
Ceylonica, Kelaart (xe, 9). 
Body limaciform, rather swollen or raised on the central region. 
Mantle obsolete; no appendages; rhinophores laminated and 
