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BRITISH FOSSIL TRIGONLE. 



Trigonia conocardiiformis, Krauss. 



Of this remarkable species, so abiiudaiit in certain districts in Southern Africa, the 

 single imperfect example in the British Museum is herewith figured. I have deemed 

 it expedient to give the subjoined figures partly to correct an error induced by the 

 reduced and inadequate figures given by Krauss, which appeared to me to represent 

 one of the ClavcllatcR ; the Museum specimen undoubtedly associates it with the 

 crcnulated examples of the ScabraB (see pp. 120, 121). 



The general figure is unusually lengthened ; the numerous curved, slightly crenulated 

 costae, widely scj)arated anteally, are much smaller and more closely arranged posteally ; 

 they all disapi)ear upon the upper surface of the valve ; the spaces representing the area 

 and escutcheon are separated and apparently plain. The specimen, which is the only 

 one known to me, is imperfect posteally, and would be slightly more lengthened when 

 entire. The interior exhibits the hinge-processes and sulcations of the left valve, massive 

 and spreading, but partially destroyed. 



This gigantic species is not without a certain resemblance, both in the general figure 

 and arrangement of the costaj, to the Belgian T. Ellsa of the Whetstones of Bracquegnies, 

 but the larger anteal costae are without the rounded papillary prominences of that 

 species. The smaller posteal costae are nearly straight and directed retrally, as in the 

 smaller Belgian form. 



Triyonid cimocardii/urmis, Krauss. South Africa. 



