(151) 



NEW FORMS OF THE HEMICHORDATA FROM SOUTH 



AFRICA. 



I. Phoronopsis albomaculata, g. et sp. n. 

 II. Phoronis capensis, sp. n. 

 III. Ptychodera capensis, sp. n. 



By J. D. F. Gilchrist, M.A., D.Sc, Ph.D., C.M.Z.S., 



Government Biologist to the Colony of tlie Cape of Good Hope. 



(With Plates XVI., XVII.) 



(Read June 26, 1907.) 



Introduction. 



The three orders of the Hemichordata''' prove to be represented 

 in South x\frica : the Enteropneusta by the form here described ; 

 the Pterobranchia by a new species of Cephalodiscus f ; and the 

 Phoronidea by the two forms mentioned above. 



A species of Phoronis is not uncommon in South African seas, 

 and individual specimens are readily obtained in limestone and 

 amongst incrustations of Polyzoa and worm tubes dredged from 

 shallow water (15 to 30 fathoms). 



A number of the animals were, however, obtained in a much 

 simpler way. About the beginning of May, 1906, numerous 

 specimens were observed in a tank at the Government Marine 

 Laboratory, and there is evidence that they had been brought in 

 with the supply water as larval forms. They were first seen in a 

 small piece of limestone which had been procured from a depth of 

 about 20 fathoms in False Bay some time previously, and it was 

 thought that they had been brought in with the stone. Further 

 search, however, in the tank resulted in the discovery of other 



* Adopting for the present purpose Harmer's subdivisions of this group (vide 

 " Cambridge Natural History," vol. vii.). 



f Vide " Marine Investigations in South Africa," vol. iv., pp. 173-192. 



