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4. On Two New Species of Ptychodera (P. proliferans and P. 

 natalensis). By J. D. F. GILCHEIST, M.A., D.Sc., PH.D. 



In addition to the species of Ptychodera (P. capensis) already 

 recorded at the Cape, another is found in fair abundance in the 

 same localities, often under the same stones, but usually nearer 

 high-water mark. Sometimes only a single specimen was found, 

 at other times several on one occasion as many as twenty were 

 found under a stone about a foot in diameter. It was noted that 

 among adult forms there were often several much smaller and imma- 

 ture individuals, and on several occasions when a single full-grown 

 specimen was found, two to six small ones occurred within a few 

 inches of it. These small forms did not vary much in diameter 

 or length, but the proboscis and collar were at all stages of develop- 

 ment, some being entirely without those organs, others with small 

 proboscis and collar incomplete dorsally, and others with all parts 

 of the body complete. There was thus apparently a process of 

 natural fragmentation or proliferation from the tail region in this 

 species. Only on one occasion was the breaking up so characteristic 

 of many other forms observed, and that in the case of an abnormally 

 long specimen, the posterior extremity of which was observed to 

 break off. That this is a normal process of multiplication in this 

 form is further indicated by certain anatomical features noted below. 

 The specific name proliferans refers to this characteristic. 



After finding these species at the Cape, I took occasion on a 

 recent visit to Natal to search for specimens on the East Coast. 

 The coast-line at several points was examined, and it was only when 

 looking for other animals in the lagoon at Durban that unexpectedly 

 a fine species of a Balanoglossus was found, which was quite 

 obviously distinct from the Cape species and seems to belong to a 

 species not yet described. A fragment only was found at first, but 

 with the aid of some men, and after prolonged digging, a complete 

 specimen was procured. The animal is so long that it is difficult to 

 secure an unbroken specimen, and in addition to this it breaks up 

 readily, unlike the two Cape species, even with careful handling, 

 one piece breaking up when merely placed in a surface pool of rather 

 warm water. The animal was very sluggish when alive, and occu- 



