APPENDIX 241 



apexes. The mollusc of this shell is edible. We came across 

 heaps of these on the Sudanese coast at Mersa Halaib. After 

 being cooked on embers or in water the animal had been 

 extracted from a hole knocked through the upper part of the 

 shell. I never tried this dish and cannot pass an opinion 

 about the taste, but apparently the natives eat it greedily. 



The species of the murex shells, also gasteropods, are 

 common on the tidemark. Of these I remember the Murex 

 temiispina with its long elegant spikes going right round the 

 shell. We collected a number of these also using the triple- 

 net on the sand bottoms. Another common murex shell is the 

 Chicoreus ramosus with a bright pink peristoma or lip. In the 

 zone of Mersa Halaib alone, we collected several harp shells. 

 This is a glossy shell with the appearance of marble and 

 ornamented with many falciform ribs. 



The cowries and volutes are the most interesting univalve 

 shells in the madreporic environment. They are exceptionally 

 beautiful and are, fortunately, found everywhere. The genus 

 Cipraea (cowrie, or in Italian porcellane^ or porcelli di mare) of 

 the Cipracidae family are collected by the natives all along the 

 coast. They are used for decorative purposes, as vases or 

 sacred ornaments. In some countries a certain species of the 

 cowrie, the Cipraea moneta, has been widely used as currency. 

 The biggest examples of this genus, for example the Cipraea 

 tigris and the Cipraea panterina, which are somewhat alike, 

 distinguished by numerous black or dark round spots on a 

 background of one colour, varying from light or dark brown 

 to violet, were found in low water averaging three feet in 

 depth. The Cipraea arabica which is rather smaller (it averages 

 three inches), of a bright black and white mosadc design or 

 sometimes a pearl grey, lives in the narrow cracks of the old 

 dead madreporic masses which form breakers to the islands 

 and the coast in many regions. But it is also not unusual to 



