51 



NOTES OX THE AXATOMY OF SOUTH AFRICAX APLYSIID^, 

 WITH DESCRIPTIOXS OF TWO NEW SPECIES. 



By R. H. BuKNK, B.A. 



Read Uth January, 1906. 



Rather more thaa a year ago, a small collection of Aplysiidae, 

 coUectefl in South Africa by Mr. Henry Bumup, was entrusted to mo, 

 through the kindness of Mr. J. H. Ponsonby, for dissection and 

 description. To both of these gentlemen I wish to express my thanks 

 for the opportunity thus afforded rae of adding somewhat to the 

 relatively scanty records of the anatomy of members of this group 

 of molluscs. 



The collection comprise^l eight specimens belonging to four species, 

 two of which are apparently new. 



Tethys opeeta, n.sp. 

 The four specimens of this species (three from Isipingo and one from 

 Scottsburg) closely resemble each other except in size, and in their 

 most important external features are so closely similar to Tethys 

 dadyhmela (Rang) and its varieties (especially var. (Bqu<>rea, Heilprin) 

 that, were it not for the complete closure of the shell-sac, it would be 

 unnecessary to consider them as anything but varieties of dactylomela. 



--'^ 



Fig. 1. 



The least distorted of the four specimens (Fig. 1) had the following 

 measurements : — Total length, 68 mm. ; breadth in front of the para- 

 podia, 21 mm. ; height in the middle of the visceral sac, 28 mm. ; length 

 of posterior extremity of the foot behind the parapodia, 9 mm. ; length 

 of the attachment of the parapodia to the body, 28 mm. ; greatest 

 depth of the parapodia, 14 mm. ; breadth between the anterior ends of 

 the parapodia, 12 mm. ; distance from the anterior end of the parapodia 

 to the rhinojjhores, 22 mm. ; distance between the rhinophores and 

 anterior tentachs, 12 mm. ; breadth between the rhinophores, o mm. 



