-120 MR. E. A. SMITH ON SHKLI.S FROM ADEN. [June 16, 



169. Trochus (Tectum) dentatus, Forskal. 



Hab. Red Sea, Persian Gulf. 



Both the typical form and the variet}' {T. noduliferus, Lr.mk.) 

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

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

 examples the nod ides at the periphery become son;ewhat obsolete upon 

 the la?t third of the whorl towards the outer lip. Their opf rcula are 

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

 which enlarge somewiiat rapidly. 



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

 Hab. Red Sea, Gulf of Suez. 



1/1. Trochus (Infundibulops) firmus, Philippi. 

 Uab. Persian Gulf. 



172. Trochus (EucHELtJs) atratus, Gmelin, 



Hab. Widely distributed. Many parts of the Indian and Pacific 

 Oceans. 



173. Trochus (Clanculus) pharaonis, Linn. 

 Hab. Red Sea, Gulfs of Suez and Akaba. 



174. Trochus (Monodonta) australis, Lamarck. 



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



All the s]iecimens from South Alrica which I have seen have 

 stronger spiral sulci and ridges tiian the examples from Aden. 

 These are nearly smooth, but precisi-ly similar in style of colouring. 



175. FiSSURELLA RUPPELLII, Soweiby. 



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



176. Patella chitonoides, Reeve. 

 Sab. Madagascar, Mauritius, Reunion. 



177. Chiton (Acanthopleura) spiniger, Sowerby. 



Hab. Suez (/we/) ; Aden (Haddon) ; also widely distributed in 

 the Pacific and Indian Oceans. 



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

 fig. 6.) 



Testa parva, depres^a, in wedio leviter cnrinata, pallide grisea, 

 sort/ido-viride maculuta ; arece laterales, centi-ales et valva 

 antica vndique subceqvalifer reticvlafce ; apex valve posfica; 

 subcentrulis, medioci'iter acutvs ; ligawetdnm sqvamis mivu- 

 tissimis indufvm, roseo-griseum, sordido-viride maculatum. 

 Longit. \h miUim., diam. 8. 



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

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

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



