264 DR. W. A. CUNNIXGTON ON 



Dolojys ranarum Bouvier, Bull. Soc. Pliilom. ser. 9, tome i. 

 1899, p. 13. 



Dolops ranarum Wilson, Proc. U.S. Nat. Mus. vol. xxv. 190H, 

 p. 737. 



Dolops ranarum Thiele, Mitt. Zool. Mus. Berlin, Bd. ii. 

 Heft 4, 1904, p. 17. 



This species was originally obtained by Stuhlmann at Bukoba, 

 on the western shores of Victoria ISTyanza, and described by him 

 under the name Gyropeltis ranarum. The specimens were 

 found attached to the surface, and occasionally at the entrance 

 of the branchial chamber, of a number of tadpoles, and on that 

 account received their specific name. It does not appear a very 

 fortunate title, however, since specimens were obtained by the 

 present Expedition from the bodies of four different kinds of 

 fish, and most of the specimens, as a curious coincidence, actiially 

 from Bukoba itself. It is, indeed, no new fact that certain 

 species of Argulidse may be found on a variety of hosts, the 

 well-known European type, Argidus foliaceus, being an excellent 

 example, as its host-list also includes frog-tadpoles as well as 

 a number of fish. The literature of the subject contains other 

 cases of similarly inappropriate specific names derived from those 

 of the hosts, and as long ago as 1875 Glaus* deprecated this 

 obvious but unsatisfactory manner of naming species. 



It may be no more than coincidence, but it is remarkable how 

 often this form was found associated with Argulus africanv,s 

 on a common host. 



Tanganyika. — Dolops ranartmi does not appear to be common 

 in Tanganyika, since it was obtained on only one occasion, and 

 then from a single large fish. The coloration of these specimens 

 differs somewhat from that stated hitherto, and, in fact, to some 

 extent from the Victoria Nyanza specimens in the present col- 

 lection. The upper surface of both carapace and abdomen is 

 irregularly covered by arborescent pigment-spots of a grey 

 colour, which are most numerous on the carapace lobes. In 

 addition, there is an irregular series of small white spots, 

 scattered without any apparent relation to the grey pigment- 

 spots already mentioned. 



Occurrence.- — Kala, 18/11/04. From mouth-cavity and gill-bars 

 of large Dates microlepis (length 910 mm.). Three male and 

 three female specimens. Associated with them were specimens 

 of Arguhcs africanus. 



Victoria Nyanza. — This is the only species of Argulid hitherto 

 known from the lake, and still seems to be the commonest, 

 although specimens of another widely distribvited form (Arguhos 

 africanus) were obtained during this Expedition. The specimens 

 of D. ranarum taken in this lake differ slightly in colour from 

 those collected in Tanganyika. They are of a more unifoi-m 

 brown colour, and show little of the arborescent grey spots above 



* Zeitsclir. f. wiss. Zool. Bd. xxv. 1875, p. 278. 



