Lakes of the Cameroon Mountain. 137 



longest anal spine. Tlie number and arrangement of scales 

 also differ; for instance, in T. Zillii there are 4-3|- scales 

 between the lat. 1. and anterior dorsal spines, and 2^ between 

 the posterior end of lat. 1. and tlie dorsal, whereas in T. kottcc 

 the same numbers are 3 and 1^. The proportions are also 

 dissimilar : in two specimens of exactly the same length the 

 head of T. kottce is 36 7o and that of T. Zillii only 31 % of 

 the total length without caudal. The colour is also different, 

 as T. Zillii has 6 to 8 dark bars and sometimes a longitudinal 

 stripe. All these particulars, together with the geographical 

 separation, induce me to establish a separate species, named 

 after Lake Barombi-ba-kotta. According to Mr. Boulenger, 

 T. Zillii is distributed from the Algerian Sahara to Lake 

 Eudolph and tlie Lake of Galilee. 



From the Tilapia lata group, T, kottce is distinguished 

 by its shorter pectorals &c. 



Mr. Linnell has obtained quite a number of specimens of 

 T. kottoi, so that the above description is based on several 

 examples. 



Tilapia dubia, sp. n. ? 



It is with much hesitation that I propose this new species, 

 as it is based on only one specimen ; but, on the other hand, 

 its markings are so distinct, and it differs so decidedly from the 

 species of Tilapia to which it might otherwise be related, 

 that it seems incorrect not to describe it separately. 



An outer series of rather large and only slightly notched 

 teeth, about l-i on each side of the upper jaw ; on the inner 

 side of this outer row two or three series of minute teeth. 

 Depth of body 2 times in total length without caudal, length 

 of head 3 times. Snout with straight upper profile, as long 

 as diameter of eye, which is contained 3 times in length of 

 head and 1^ times in interorbital width. Maxillary extend- 

 ing to between nostril and eye. Three series of scales on the 

 cheek ; large scales on the opercle. Gill-rakers short, 13-1 J: 

 on lower part of anterior arch. Pectoral pointed, much longer 

 than head, and extending a good deal beyond the origin of 

 anal. Ventral not produced reaching vent but not beyond. 

 Dorsal XVI 13, spines subequal from the fifth, about ^ length 

 of head. Anal III 10, third spine stouter than dorsal spines, 

 but of nearly the same length. (Caudal mutilated.) Caudal 

 peduncle nearly 1^ as deep as long. Scales cycloid, probably 

 about 27-28 f|, lat. lin. ^. An opercular black spot, another 

 at the base of the anterior soft rays of the dorsal. Eight dark 

 bars, the first just in front of the opercular spot, the second 



