OF FISHES FROM LAKE TANGANYIKA. 5 
proposition enunciated above. Lake Tanganyika might be regarded as the centre of 
origin of all the African genera of Cichlid. 
Unfortunately, nothing reliable is yet known of this family in a fossil condition, with 
the exception of a few American Tertiary types, which do not differ materially from 
those inhabiting the same part of the world at the present time. There is no reason for 
referring to it the Cretaceous fishes from Mount Lebanon described as “ Chromides”’ 
by Heckel! and by Davis®. All we can gather from Heckel’s description is that 
Pycnosterynaz is based on some “ Pharyngognath Acanthopterygian,” and that it does 
not belong to the Cichlide is conclusively proved by his statement: ‘“ Rippen kurz, 
diinn, die hinteren auf langen Querfortsatzen ansitzend,” a sentence that has been 
translated by Davis as “ Ribs short and slender, the posterior ones supporting long 
transverse apophyses”°. An examination of some of the specimens of Pycnosteryna 
exhibited in the British Museum suggests to me special relation to the Berycidw, with 
which they are provisionally associated by Mr. Smith Woodward, and certainly no 
affinity to the Cichlid. Considering that coalesced lower pharyngeal bones occur at 
the present day in such widely different groups ns the Serrande, Gerride, Scienide, 
Cichlide, Pomacentride, Embiotocide, Labride, Scaride, Pleuronectide, and Scombre- 
socid@, this character, if correctly ascertained by Heckel, would in itself be no serious 
objection to the allocation of Pycnosterynz among the Berycide. Giinther* also 
doubts the correctness of Heckel’s determination when he states that ‘ the position 
of Pycnosteryna is uncertain,” but we are not enlightened as to its affinities by the 
further remark that “it approaches certain Pharyngognaths.” It appears certain that 
true Peérciform fishes, to which large group the Cichlid belong, have not yet been 
described from pre-Tertiary beds. 
In order to show what is now known of the fish-faunas of the great lakes, lists are 
appended of the fishes of Lakes Nyassa, Tanganyika, Victoria Nyanza, and Rudolf. 
These lists must of course be faken as giving a very inadequate idea of the fauna, 
owing to the incompleteness of the collections on which they are based; but, imperfect 
as they are, they nevertheless will prove useful as a basis from which to judge of the 
relation existing between the piscine inhabitants of these lakes. Of the other lakes, 
unfortunately, nothing can be said at present, the occurrence of an undetermined species 
of Haplochilus in the Albert Nyanza being all the information we possess. 
the lower forms. In the Teleosteans, as a general rule, the lateral lines are reduced to one on each side, 
extending uninterrupted from the head to the root of the caudal fin, although among this order there is 
hardly a single large group that does not offer exceptions such as are shown in the Cichlide. In these, both 
upper and lower lateral lines may be complete ; or the upper may be complete and the lower reduced, or the 
reverse; or the upper may be incomplete posteriorly and the lower anteriorly, which latter disposition has led 
to the misconception involved in the term “ interrupted.” 
1 Apbild, u. Beschr. n. Thier. Syrien, p. 235 (1843). * Tr. R. Dublin Soe. (2) iii. 1888, p. 531. 
5 L.c. p. 532. 4 Study of Fishes,’ p. 200 (1880). 
B2 
