ANIMALS. 93 



Genus Strophalosia, King, 1844. 



Spondylus (Goldfussi), Munster, 1839. 

 Orthis (excavata), Geinitz, 1842. 

 Strophalosia (= Lept^nalosia), King} 1844. 

 Productus, de Ferneuil, 1845. 

 (?)AuL0STEGES, JJe/OTersoWj 1847. 

 Orthothrix Geinitz, 1848. 



Biagnosis. — A Productidia having the large valve (occasionally the small one) 

 furnished with an area divided by a deltidium ; and both valves articulating by means 

 of teeth and sockets, — the former situated on each side of the base of the deltidium of 

 the large valve, and the latter on each side of the boss or cardinal muscular fulcrum 

 of the small valve. 



Type, Orthis excavata, Gem\tz=Strophalosia spinifera, King.^ 



In a paper published in the ' Annals and Magazine of Natural History,' for 

 November 1844,1 announced my intention of instituting the present genus^"fora 

 Productus-like shell with an area, and possessing a condyloid (condyliferous) hinge, as 

 in Terebratulse, and not a simple one, as in the true Producti :" and in my paper 

 on the ' Palliobranchiata/ subsequently published in the same journal, I entered 

 into some details on this group, showing its distinctiveness, and how it dijBfered from 

 Productus, a closely-allied generic form. Since the last paper appeared. Colonel von 

 Helmerson^ has proposed the genus Aulosteges for a singular shell (named by himself 

 A. variabilis) occurring rather abundantly in the Permian limestones of Mount Grebeni 

 in the North of Orenbourg, Russia, and which is now known to be identical with 

 M. de Verneuils Orthis Wangenheimi. Colonel Helmerson considers this genus to be 

 distinct from my Strophalosia ; but I regret that its principal distinctive features are 

 not so clearly shown as could be desired. The presence of spines on the deltidium* 

 constitute, in my opinion, the only distinctive character; but I am not prepared 

 positively to deny the existence of deltidial spines in Strophalosia, though, with the 

 exception of some obscure indications (in the form of irregular risings on the deltidium) 

 in S. Goldfussi, they do not appear to be characteristic of the species herein described. 



' The name Leptcenalosia, a mere provisional MS. name noticed in the 1st vol. of the Geology of Russia, 

 was shortly ahandoned for the one now adopted. 



2 Vide Annals and Magazine of Natural History, vol. xviii, p. 28. 



3 " Aulosteges variabilis, ein neuer Brachiopode mit articulirtem Schlosse, aus dem Zechstein Russlands," 

 von G. Von Helmerson; Lu le 22 Janvier 1847: and published in the Bulletin de la Classe Physico- 

 Mathematique de I'Academie des Sciences de St. Petersbourg, t. vi, No. 9. 



* Mr. T. Davidson assures me, that both he and M. de Verneuil, from an examination of specimens in the 

 latter gentleman's collection, are convinced that spines do exist on the deltidium of Aulosteges variabilis 

 = Orthis Wangenheimi, a character of which I have hitherto entertained some doubt. 



