462 CARBONIFEROUS LAMELLIBRANCHIATA. 



Grassiiigton ; Duumow Quarry, Slaidburn ; Teenley Quarry and Settle, Yorkshire ; 

 Park Hill and Thorpe Cloud, Derbyshire; Narrowdale, Staffordshire ; the Fourlaws 

 Limestone, the Coomb, Redesdale. Ireland : the Carboniferous Limestone of 

 Queen's Co., Enuiskilleu, co. Fermanagh. Scotland: the Lower Limestone series 

 of Corrieburn, Kilsyth. 



Observations. — The specimens figured by Sowerby (op. cit.) as the types of 

 Cardium alseforme are preserved in the Sowerby Collection in the British Museum 

 (Natural History), Cromwell Road, and I am permitted to refigurethem, PI. LIV, 

 figs. 1 and 2, by the kindness of the authorities. Neither specimen is perfect, 

 but both of them are sufficiently typical of the general character of the species ; 

 and I do not agree with Prof. Phillips that the lower figure, of which only the 

 posterior end was shown, appears to belong to his Pleurorliynclms minax. 



I have no doubt that Cardium armatum, Phillips, is the young of C. alseforme, 

 Sow., and 1 refigure the type of this species, which is preserved in the Gilbertson 

 Collection in the British Museum (Natural History branch), PI. LIV, fig. 3. 



De Koninck in 1842 (op. cit.) considered these two species and P. minax to be 

 identical, but in his later work reversed this opinion. He states that C. armatum 

 is distinguished from G. aliforme by being much less oblique, with a more slender 

 rostrum, and by a larger number of radiating ribs. The first two of these 

 distinctions so evidently depend on the state of growth of the shell that no 

 further discussion is necessary. Moreover, the number of radiating ribs depends 

 on the layer of shell which is examined, the lower layers having much fewer ribs 

 than the surface — a fact shown in Sowerby's type, PL LIV, fig. 2, but on the 

 opposite side to that figured. 



C. 'minax is a species about which there has always existed a great deal of 

 uncertainty, and unfortunately there is no type to refer to, as the specimen 

 which served for the description by Phillips has disappeared. Added to this is 

 the fact that Phillips thought that the lower figure of G. aliforme of Sowerby 

 was P. minax ; and that de Koninck, in his early work, and M'Coy considered 

 Phillips's species a synonym of Sowerby's G. aJ forme. 



Phillips's figure seems to rae to have been an impossible one, and to have been 

 drawn at the same time from two points of view ; and unfortunately the 

 description, which is as follows — " anteriorly gibbous and rounded, posteriorly 

 elongate, rostrum attenuated, radiating furrows equal" — is too meagre to permit 

 any decision to be formed from it : at the same time it presents no marked differ- 

 ences from G. aliforme. 



De Koninck in his later work [op. elf.) has re-described G. minax, but his 

 figure seems to me to have little in common with that of Phillips, and to be quite 

 different from the specimens labelled G. minax in our museums. It is a small 

 individual with apparently a much closer affinity to G. ivflatum. 



