338 Annals of the South African Museum. 



PISCES. 

 TELEOSTOMI. 



GEN. SEMIONOTUS, Ag. 

 SEMIONOTUS CAPENSIS, Sm. Woodw. 



1888. Smith Woodward. Quart. Journ. Geol. Soc, XLIV, p. 138. 

 1901. Schellwien. Schrift. Physik.-oekonom. Gesell. Konigsberg. 



XLII. 

 1909. Broom. Ann. S. Afric. Museum VII, part 3, p. 262. 



Since Broom's description, the South African Museum lias received 

 no further examples of this well-known fish, and it will suffice to 

 quote the main points of Mrunm's analysis of the form. 



"The majority of specimens measure from 160 to 210 mm. in length. 

 In the example which is 210 mm. long, the body is 42 mm. in 

 depth at the deepest part, and the head measures 48 mrn. to the 

 back of the operculum. 



Schellwien has recently described a number of specimens and has 

 shown the more important features of the skull structure. The 

 specimens I have examined confirm most of his observations, but in 

 one or two points I am inclined to differ from him. 



Almost every detail of the skull is now known except the basi- 

 cranial region. The frontals are large, and extend from the nasal 

 region to behind the plane passing through the back of the orbit, 

 The back part of the bone is about twice as wide as the middle 

 portion. Behind it is a large oblong parietal. Below the parietal is 

 a slightly narrower squamosal. My specimens do not satisfactorily 

 show the supratemporal region, but Schellwien linds a narrow 

 supratemporal and a post-temporal. 



The opercular bones are very like those of Lepidoius. The oper- 

 culum differs in being relatively considerably wider in its lower 

 half. Inferiorly it joins the subopercular in a manner very similar 

 to that in the better known genus. The subopercular in Semionotus 

 is only about one-third the size of the operculum instead of half as 

 large as in Lepidotus, while the interopercular is less than half the 

 size of that in Lepidotus. In front of these three opercular bones 

 is a narrow curved preopercular, along which there runs a mucous 

 canal. 



In Schellwien's diagrammatic restoration the postorbital seems to 



