belonging to the Class Palliobranchiata. 89 



ferida, and the latter in that of Terebratulida. Besides its sub- 

 gyrate processes and its deltidium (which when the shell is 

 young has precisely the character of that of the Spirifers), its 

 close resemblance to Martinia [Terebratula) hyalina, Buch, both 

 as regard external characters and the crural base, are eminently 

 in favour of Strigocephalus belonging to the Spiriferidce ; and 

 the probability is even great that it is directly allied to the genus 

 Martinia. 



Camerophoria. 



Some years ago I was struck with the remarkable difference 

 between the casts of a magnesian limestone Terebratula and 

 those of every other species with which I was then acquainted. 

 Judging from casts of the dorsal valve of the latter, it was 

 obvious that the umbonal cavity had been either furnished with 

 two vertical condyle plates, generally divaricating as they passed 

 from the beak, or unprovided with any kind of armature ; but 

 in the former there had evidently been an arch-shaped process, 

 suspended from the roof of the umbonal cavity by a shallow 

 plate. The contrast between casts of the magnesian limestone 

 shell and of certain carboniferous species {Hypothyris pleurodon, 

 H. pugnus, &c.) closely allied to it by external characters, was 

 particularly striking. In 1840 Dr. Goldfuss kindly favoured me 

 with some casts of a fossil labelled " Pentamerus Knightii from 

 Hohenzolen," when I was immediately struck with their resem- 

 blance to the magnesian limestone species, which I at once con- 

 cluded to be a Pentamerus; but on a further comparison I 

 became convinced that there was a decided difference between 

 them in the apophysis of the ventral valve. M. Verneuil also 

 appears to have been at first led to suppose that the magnesian 

 limestone shell, specimens of which he collected in Russia, was 

 a Pentamerus ; but though M. Verneuil and myself are now satis- 

 fied that this was an error, we differ in opinion as to the value 

 of the internal structure which belongs to the shell in question : 

 M. Yerneuil considers it not sufficiently marked to form a ge- 

 geric character; while I am led to believe that it ought to be 

 regarded as diagnostic of a new genus, for which the name Ca- 

 merophoria is proposed. 



Having, by the examination of a large number of specimens 

 of the typical species (C. [Terebratula'] Schlotheimi) in various 

 states of preservation, satisfied myself regarding the internal 

 characters of Camerophoria, I will now proceed to describe them 

 with reference to their generic value. 



The upper or rostral valve possesses a deltidium, which is open 

 and only exposed in young individuals ; in old ones it becomes 

 dilated at its base, and is then occupied by the umbone of the 



Ann. fy Mag. N. Hist. Vol. xviii. H 



