On a Stridulat'mg-organ in certain River- Crahs. 4G9 



solely to Seba's admirable figure of the Slender Loris, and this 

 should therefore be taken as the basis of the Linnean name. 



The fact tliat Linnaeus many years afterwards referred to 

 his Lemur tardigradun a specimen of a Nycticebus wfiich he 

 then described, should not be allowed to affect our judgment 

 as to what was the original and essential basis of the name 

 he gave. 



Loris tardigradus will therefore be tlie proper name of the 

 Cinghalese animal, while Dr. Cabrera is of course right in 

 saying that of Mr. Lydekker's two sub-species of Lori>i* it is 

 the S.- Indian one which needs the new name. He gives 

 to this that of Igdekkerianus, the co-types of which would be 

 those referred to by Mr. Lydekker, B.M. nos. 3. 2. 19. 1-2. 



Further, 1 am at issue both with Dr. Cabrera and Mr. Lyon 

 in their contention tiiat the name menagensis is to be treated 

 as "won est" in the group. For while this was the case on the 

 descrijjtion of the animal when first published by Nachtrieb 

 without a generic name, its reference to the genus Nijcticehus 

 by 'JVouessart f has technically to be taken as a giving of the 

 name menagensis to the animal described by Nachtrieb, the 

 name theretore having now validity as Nycticehus menagensis^ 

 Trouessart. The latter's " ? ^' does not affect the question, 

 as, although with the query, the animal is put into the genus 

 Nycticehus, and also without a query by Stone and E-ehn | 

 and Lydekker §, on whose authority, again, menagensis would 

 antedate the new name philippinus given by Dr. Cabrera. 



LXXVI. — On a Stridulating-organ in certain African River- 

 Crabs. By W. T. Calm AN, D.8c., British Museum 

 (Natural History). 



In examining a collection of river-crabs (Potamonid^e) 

 rt-cently brought to the British Museum from the Gaboon 

 by Dr. W. J. Ansorge, I observed in one of the species a 

 stridulating-organ of a type hitherto undescribed. A search 

 among the Putamonidse of the IMuseum collection revealed 

 tlie fact that a similar organ is present, though less perfectly 

 developed, in certain other species more or less closely related 

 to the first. 



The species which presents this structure in its fullest 



♦ P. Z. S. 1904, ii. p. 345, pi. xxiii. 

 + Cut. Maniiu. i. p. 03 (1698). 



t L. c. p. 138. § Z. r. p. 34o. 



Ann. cfc Mag. X. Hist. Ser. 8. Vol. i. 3i 



