1907.] ON MEDUSAE FROM AFRICAN LAKES. 643 



The Lamprididse, Yeliferidte, and Lopliotid?e have at one time 

 or another been supposed to be i-elated to the Scombriform 

 Acanthopterygians, but these are a much more specialised group, 

 without an orbitosphenoid and typically with a spinous dorsal fin, 

 the anal preceded by sjDines, the ventrals composed of a spine and 

 5 soft rays, and the pelvic bones directly attached to the clavicles. 



Boulenger has placed Lampris near the Gastrosteidfe, on the 

 ground of an interpretation of the elements of the pectoral arch 

 which has not received acceptance, but these difler widely from it 

 in their anatomy and seem probably to have originated from the 

 Haplomi near the Oyprinodontidse and Scombresocidse. 



Jordan has stated that the Eocene Semiophorxis is related to 

 Lampris. Dr. Smith Woodward very kindly looked at the speci- 

 mens of the extinct genus in the British Museum with me, and it 

 seems on the whole probable that Semiophorus is not related to 

 Lampris and Veli/er, but to Platax, near which genus Dr. Smith 

 Woodward has placed it. 



In Semiophorus the vertebrae are 24 in number, the dorsal fin 

 is covered with small scales, the anal fin is preceded by 3 spines, 

 and the outer ray of the ventral fin is a short spine. It is probable 

 that the soft rays of the venti'al fin are 5 in number and much 

 branched, and not so numerous as would appear from the current 

 representation of this fish. 



The Tseniosomi wer-e regarded by Dr. Gill as possibly derived 

 from the same stock as the Pleuronectida^ ; whilst Boulenger, on 

 the ground of the large number of rays in the ventral fins, con- 

 sidered them as pi-obably related to the Beryciformes. 



The remarkable Stylophorus has usually been placed with or 

 near the Trachypteridae. The single known specimen is not in 

 good enough condition for me to ofiei' any suggestion as to its 

 relationships. 



6. Zoological Results of the Third Tanganyika Expedition, 



conducted by Dr. W. A. Cuunington, 1904-1905. — 



Report on Limnocnida tanganicce ; with a Note on 



the Subspecies from the Victoria Nyanza. By R. T. 



G-iJNTHER, M.A., F.R.G.S., Fellow o£ Magdalen College, 



Oxford *. 



[Received May 22, 1907.] 



(Plate XXXVII. t & Text-figures 172-174.) 



The collection of the jelly-fish of Lake Tanganyika made by 

 Dr. Cunnington in 1904 and 1905 is the best which has yet 

 been brought to this country. 78 individuals, some in several 

 hitherto undescribed stages of development, were obtained from 

 three localities at four different dates from September to February, 



* Communicated by the Secretary. 



t For explanation of the Plate, see p. 656. 



