The Invertebrate Fauna of the Uitenhage Series. 155 



GENUS SOLECUETUS H. D. de Blainville. 



SOLECURTUS Sp. 



Text-figure 1. 



Description of a Single Specimen. The specimen is a right valve, 

 slightly imperfect at the siphonal margin. The umbo is very incon- 

 spicuous, and is situated slightly in front of the middle of the shell. 

 The upper margin slopes down very gently in front and behind the 

 umbo. The frontal margin is short and has a rounded convex 

 profile ; towards this margin the upper and lower valve-borders very 

 gently converge. Towards the siphonal margin the valve has a 

 slightly greater height than in the anterior half. The surface is 

 marked by lines of accretion, but no trace of ornamentation has 

 been observed. The inflation of the valve is very slight. 



FIG. 1. Solccurtits sp., nat. size. Survey Collection. 



Dimensions. 



Length (if restored) 31 mm. 



Height at the umbo 12 ,, 



Depth of the valve, about 3 ,, 



Length of siphonal margin 9 , , 



Length of frontal margin 6 , , 



Occurrence. Found at Grass Eidge, 3 miles east-north-east of 

 Uitenhage (310). 



Remarks. The single specimen examined is not quite complete 

 at the posterior end, and, unfortunately, the surface is so preserved 

 as to leave no traces of faint linear sculpture, if such markings were 

 ever present. By following the growth-lines it is possible to arrive 

 at the original form of the posterior border. In shape the shell 

 agrees very closely with Solecurtus warburtoni Forbes,* from the 

 Aptian of Atherfield (Isle of Wight) ; the umbo occupies a similar 

 position, and the valve is anteriorly rounded, with diminished height 

 towards the frontal border, while posteriorly the height is greater. 

 The only clearly observable difference is that, in specimens of similar 

 dimensions, the measurement from the umbo vertically to the 

 inferior margin is relatively rather smaller in the English shell. 



* Forbes (1), p. 237, pi. ii., fig. 1. 



