-^20 MR. E. A. SMITH ON SHELLS FROM ADEN. [JunC 16, 



169. Trochus (Tectum) dentatus, Forsk&l. 



Hab. Red Sea, Persian Gulf. 



Both the typical form and the variety {T. noduliferus, Lr.mk.) 

 occur at Aden. Of the latter some specimens are very large, being 

 69 millim. in height and 100 across the base. In these very fine 

 examples the iiodnles at the fieriphery become Fon.ewhat obsolete upon 

 the lat-t third of the whorl towards the outer lip. Their opercula are 

 37 millim. in diameter, thin, yellowish brown, and consist of 12 whorls 

 which enlarge somewhat rapidly. 



170. Trochus (Infundibulops) ekythr^us, Brocchi. 

 Hab. Red Sea, Gulf of Suez. 



171. Trochus (Infundibulops) firmus, Philippi. 

 Hab. Persian Gulf. 



O 



172. Trochus (EucHELUs) atratus, Gnielin. 



Hab. Widely distributed. Many j)arts of the Indian and Pacific 



173. Trochus (Clanculus) pharaonis, Linn. 

 Hub. Red Sea, Gulfs of Suez and Akaba. 



174. Trochus (Monodonta) australis, Lamarck. 



Hab. Natal, Seychelles, Madagascar ; Gulf of Suez. 



All the specimens from South Africa which I have seen have 

 stronger s|)iral sulci and ridges than the examples from Aden. 

 These are nearly smooth, hut precisely similar in style of colouring. 



175. Fissurella ruppellii, Sovverhy. 



Hab. Mauritius, Red Sea, East Africa, Mergui. 



176. Patella chitonoides. Reeve. 

 Hab. Madagascar, Mauritius, Reunion. 



177. Chiton (Acanthopleura) spiniger, Sowerhy. 



Hab. Suez (/s*eZ) ; Aden (Haddon) ; also widely distributed in 

 the Pacific and Indian Oceans. 



178. Chiton (Ischnochiton) yerburyi, (Plate XXXIII. 

 fig. 6.) 



Testa parva, depressa, in wedio levite?' carinata, pallide grisea, 

 sordido-viride maculuta ; arecB laterales, centrales et valva 

 aniica vndique subceqvaliter reticvlatce ; apex valvar ■posticcB 

 subcentralis, mediocriter acutvs ; liy amentum sqvamis minu- 

 tissimis indutum, roseo-gr\seum, sordido-viride maculatum. 

 Longit. \f) millim., diam. 8. 



Only a single specimen of this species was found by Major Yer- 

 bury. The sculpture recalls that of a thimble. It is a trifle coarser 

 on the lateral, especially along their posterior margins, than on the 



