1905.] MR. G. A. BOULEXGBR ON FISHES FROM LAKE CHAD. 151 



a cross between four species, namely, the Mallard, Spotbill, Pintail, 

 and New-Zealand Duck. 



In conclusion, Mr. Bonliote said that it was far too early in his 

 experiments to do more tha,n quote the bare facts ; but that, from 

 the facts he had laid before them, there could be no doubt that 

 hybridisation tended to produce variations that followed on the 

 lines of the pcecilomeres, and that in so doing resemblances were 

 shown towards other species that had no part in their parentage. 



Mr. G. A. Boulenger, F.R.S., exhibited a series of Fishes from 

 Lake Chad and the Shari River, collected and presented to the 

 British Museum by Capt. G. B. Gosling, and offered the following 

 remarks : — 



The fact that so many species of fishes are common to the Xile 

 and the Senegal- ISTiger, now so widely separated, has long ago led 

 ichthyologists to assume a former communication, in times geo- 

 logically recent, between these river-systems, and to regard Lake 

 Chad as probably representing the dwindling I'emains of a series 

 of lakes by which this communication was effected. But, with 

 the exception of a series sent to the Paris Mviseum a few months 

 ago and not yet reported upon in a published form, the fishes 

 of Lake Chad and the rivers that flow into it had never been 

 collected. Thanks to Capt. Gosling, we are now able to draw up 

 the following list of 23 species, belonging to 7 families : — 



MoRMYRiD^. Petrocephalus heme Lacep., Mormyrus caschive 

 Hasselqr {jitbelini C. & Y.), Hyperojyistts bebe Lacep., Gym- 

 narchus niloticus Cuv. 



Characinid^. Hydrocyon hrevis Gthr., Alestes baremose 

 Joannis, A. dentex L., A. nurse Riipp., Dlstichodus rostratus 

 Gthr., D. brevipinnis Gthr., Citharinus citharus Geoffr. 



Cyprinid^. Labeo horie Heck, (senegalensis C. & Y.). 



SiLURiD^. Glarias lazera C. & Y., Heterobranchus senegalensis 

 C. & Y,, Schilhe tnystus L., Glarotes laticeps Riipp., Bagrus 

 bayad Forsk., Synodontls darias L., 6'. batensoda Riipp., 

 /S'. serratus Riipp. 



SerraniDtE. Lates niloticus Hasselq. 



CiCHLiD^. Tilapia nilotica L. 



Tetrodontid^. Tetrodon fahaka Hasselq. 



All these species, without a single exception, are common to 

 the Nile and the Niger, thus realising in a most striking manner 

 our anticipations. 



The foUowing papers were read :- 



