429 REPORT—1905. 
from the Eocene, has twenty-four vertebrie, its nearest living allies, Clinus and 
Cristiceps, having at least thirty-four. Even the Scorpenide, one of the families 
on which Professor Jordan based his theory, and in which the vertebra vary from 
twenty-four to thirty-seven in living genera, confirm my conclusion, since their 
Eocene precursor, Ampheristus, has the lower number. I might mention other 
examples, derived from the living Seombriformes and Perciformes, to show that 
evolution must have proceeded in the same way. 
Things being so, the view which I entertained when first studying the 
Cichlids of Lake Tanganyika must be abandoned, and the direction of the sup- 
posed lines of evolution reversed, together with the signification given by me to the 
characters of increased number of dorsal and anal rays, or of multiple lateral 
lines which go more or less hand in hand with the increase in the vertebral 
segments. I must therefore repudiate the statement, first made by me in 
describing some of the new genera discovered by Mr. Moore in Lake Tanganyika, 
that they show features of generalisation, the contrary being the case. This has 
been shown by Dr. J. Pellegrin, who has recently published a monograph of the 
whole family Cichlide, in which he has very ably dealt with the question of the 
interrelation of the various genera from the phylogenetic point of view. 
Two theories have lately been put forward as to the origin of the African 
Cichlids. 
According to Mr. Moore, to whom-;we owe the discovery of so many new 
forms in Lake Tanganyika, the Cichlids are of marine origin, and penetrated into 
a hypothetical Central African sea in pre-Tertiary times. But asno Perciform 
fish of any sort is known earlier than the Upper Cretaceous, and no Perch, in the 
widest sense, before the Lower Kocene (Prodates), the possible existence at that 
remote time of so specialised a type of Perches as the Cichlids is absolutely 
contrary to paleontological evidence. Further, such an explanation is unsup- 
ported by any geological data, no trace of Jurassic or Cretaceous deposits having 
been found on the plateau of Central Africa, notwithstanding much search over a 
considerable portion of the Congo State. It is impossible to imagine that such a 
sea could have existed without leaving any sedimentary deposits whilst its 
relics were being preserved in Lake Tanganyika. Besides, the distinguished 
Belgian geologist, Professor J. Cornet, who has paid special .attention to this 
question, and has himself surveyed a considerable part of the territory of the 
Congo State, regards the Tanganyika as-by no means a very ancient lake, its 
formation not dating back beyond Miocene times. I may also here point out 
that Mr. Moore’s interpretation of the affinities of the so-called ‘halolimnic’ 
Mollusca have not received any support from those best able to judge of its 
merits. Mr, E, A. Smith, from the recent conchological, and Mr. Huddleston, 
from the paleontological point of view, have recently discussed his conclusions, 
with which they are unable to agree. I need hardly add that the discovery since 
the publication of the ‘Tanganyika Problem’ of the Medusa Limnocnida 
tanganice in Lake Victoria has dealt a further blow to Mr. Moore’s theory. 
As regards the origin of this Medusa, recent palecontological discoveries afford a 
much more rational explanation of the presence in Tanganyika of a Coelenterate of 
unquestionably marine derivation. The highly important finds of fossils between 
the Niger and Lake Chad by the English and French officers of the Boundary 
Commission, which have been reported upon by Professor de Lapparent, Mr. 
Bullenj Newton, and’Dr.'Bather, have conclusively established the existence of 
Middle Eocene marine deposits over the Western Soudan, and the Egyptian 
end Indian character of these fossils, as well as of others previously obtained in 
Cameroon and Somaliland, justifies the belief in a Lutetian (Middle Eocene) sea 
extending across the Soudan to India. In fact, as stated by Mr. Newton, the 
paleontological evidence seems to prove that the greater part of Africa above the 
equator was covered by sea during part of the Eocene period. On this sea 
retreating northwards, after the Lutetian period, Meduse# became land-locked and 
gradually adapted themselves to fresh water: they had not far to travel to find 
themselves in what are now the Nile lakes, and later, through the changes whieh 
Mr, Moore himself has shown to have taken place in the drainage of Lake Kivu, 
