33 



IV. — Asteroidea of Portuguese East Africa, collected by Jas. J. 

 Simpson, M.A., B.Se. (1907-i9()fi). By Jas. J. Simpson, M.A., 

 B.Sc, and R. N. Rudmose Brown, ixSc. 



(Received r2th October 1909. Read •22nd November 1909.) 



The present collections were made on the Mozambique Coast of Portuguese 

 East Africa, between September 1907 and May 1908. The portion of the 

 coast on which faunistie work was done extends from near Cape Delgado 

 in 10° 42' S., to Pemba Bay (Maunhane Point), 12° 58' S. 



Very little work of this nature has been done on the western shores of 

 the Indian Ocean, so that, although the collections made by the E.I.M.S. 

 " Investigator " have done much to elucidate the fauna of the eastern 

 side, our knowledge of the fauna of the east coast of Alrica is very scanty. 



The present collections therefore may help in some measure to fill in 

 many gaps in our knowledge, both of the Indian Ocean fauna in general 

 and in the distribution of many tropical forms in particular. 



The collection of Asteroids consists of fourteen named species, but in 

 addition to these we have described four species which we have at present 

 refrained from naming. The latter include two species of Pentaceros and 

 one of Anthenea ; they are probably all young forms, so that although it 

 has been impossible to refer them to any known species we do not feel 

 justified in describing them as new. A study of different stages of growth, 

 in other species of Asteroids, has convinced us that it is almost impossible to 

 be certain of any species from a young specimen, and we strongly agree with 

 Professor F. Jeffrey Bell that the application of new names to what may be 

 young and immature stages is a course to be thoroughly condemned. A very 

 good example of this is the species Linckia marmorata, which we have here 

 described in some detail, as from the original description, based on a young 

 specimen, it is almost impossible to identify mature individuals. 



We have, however, given short descriptions of the essential diagnostic 

 features ot' these young forms, as they may, by comparison with others, help 

 to form a series of developmental stages in definite species. 



We have attempted to show the geo^iraphical range of those species which 

 occur on this coast. Archaster nngulaUcs is here recorded for the first time 

 from the western side of the Indian Ocean ; and Luidia aspera appears to be 

 new for the East coast of Africa. 



The bathymetrical range in distribution and the nature of the associated 

 bottom has also been recorded when possible, and a comparison made with 

 other records. 



Numerous observations on colour schemes have been given, and these, 



e 



