TIL API A. 527 



7 Lake Suksuki, 3900 feet.— Zaphiro, 15.12.05. 



2 Modjo R. (Webi Shebeli). — Neumann and Erlanger, 1900. 



1 Lake Abaia. — Dr. Donaldson Smith, 1895. 



1 Lake Gandjule, S. of L. Abaia. — 0. Neumann, 1901. 



11 Lake Gandjule. — Zaphiro, 10.9.05. 



1 N.E. of Lake Rudolf.— Zaphiro, 6.8.05. 



7 Ergino R. (Omo), 3000 feet.— Zaphiro, 8.7.05. 



9 Mwangaden R., Brit. E. Africa.— Prof. Gregory, 1893. (Types of C. spilurus.) 



1 Pangani R., E. Africa.— Sir L. Playfair, 1865. 



7 Near Tanganiko, coast of Brit. E. Africa. — Percival, 1901. 



1 Lake Chad.— Capt. Gosling, 1904. 

 10 Kaedi, Senegal.— Delhez, 1899. 



2 Niger.— W. A. Forbes, 1883. 



1 Mureji, Upper Niger.— Budgett, 1903. 

 1 Abo, Lower Niger. — Dr. Ansorge, 1902. 



17 is the usual number of dorsal spines in specimens from the Nile, but in the 

 Mediterranean lakes 16 predominates. Thus out of sixteen specimens from Lake 

 Menzaleh, six have 15 spines, eight have 16, and 17 and 18 occur only once ; out of 

 six specimens from Lake Borollos, five have 16 spines and one has 15; out of fifteen 

 from Lake Mareotis, eight have 16 spines, three have 15, two have 17, and one has 

 18; whilst 16 spines occurs fifteen times out of twenty specimens from Lake Edkou, 

 two having 15, two 17, and one 18. 



Males grow to a larger size than females, and have the dorsal and anal fins more 

 produced, but the difference is so slight that it is unsafe to pronounce on the sex 

 without examining the genital glands. The smallest female carrying eggs or young 

 in the mouth measures 115 millimetres, the largest 350. 



Fig. 36. 



Young Tilapia nilotica. x 6. 



The nursing habit which this species has in common with so many members of the 

 family Cichlidse was first pointed out fjy me in a female from Lake Galilee, forming 

 part of Canon Tristram's collection. But it is universally known to the fishermen 

 of Egypt, who, Mr. Loat says, firmly believe that the eggs get into the mouth by a 

 reversed mode of parturition. Mr. Loat has observed in Lake Menzaleh and in the 

 Nile that the fish makes holes for breeding purposes and that when anyone 

 approaches the hole the parent swims round and round the outside to drive away the 



