184 LÖNNBERG, NOTES ON FISKES COLLECTED IN THE CAMEROONS. 



GynDiolahes typus GÜNTHER forma heteroeercalis LÖNNB. 



Two specimens of this peculiar tisli are preserved by Mr. 

 Sjöstedt from the Cameroons. The larger measured 24^/2, the 

 smaller nearly 12 cm. The luimber of rays in dorsal and anal 

 lins is the same as is recorded by Günther ^) as is also the 

 case with the relative measurements of the head, barbels and 

 body; moreover the characteristic shape of the head is the same 

 as in the picture given by Günther (m. c. Pl. 3 lig. A). There 

 would thus not be any doubt whatever about the identity of these 

 two specimens, if not the shape of their caudal fin was so pe- 

 culiar, for it is heterocercal to its exteriör shape, especially in 

 the larger specimen. It has however no corresponding change in 

 the interiör structure, hut this form is given to the caudal fin 

 by its bending upwards a little, to a doser connection with the 

 dorsal than with the anal fin. The pectoral spine is serrated on 

 both sides. Number of ventral rays six (5 according to Günther). 



The postbranchiaL cavity is well developed and contains a 

 rather large postbranchial organ with several processes on the 

 fourth branchial arch (none on the second and third, on which 

 Günther found »simple securiform» processes). ^) 



Pimelodus guttatus n. sp. 



Two specimens from the river N'dian must be referred to 

 this genus, but I have not been abie to identify them with any 

 species hitherto desoribed.^) They show themselves belonging to 

 the group Pimelodina by not having any of the, from each other 

 remote, nostrils provided with a barbel. The palate is toothless 

 and the gillmembranes notched in the middle. The dorsal fin 

 has only 7 soft rays. 



Both specimens are quite different from the two already 

 known african Pimelodonts, Pimelodus jylatychir Günther and 

 Pimelodus halayi Sauvage, by relative measurements, number of 

 rays etc. as can be seen from the following description. 



') Anm. and Mag. of Nat. Hist. Bd. XX London 1867 p. 111. 



") I do not know if this difference is of specific value. 



•*) In .some respects they resemble Ancheiiaspis biscutatus Geoffe. 



