CLASSIFICATION OF THE BRACHIOPODA. 89 



Genus — Un cites, Def ranee, 1828. 



Type—\J. GRYPHUS, Schl., sp. Int., PI. VII, figs. 79—86. 



Tebebratulites (part), Schloth. 



Uncites, Defrance, and of the generality of Authors. 



Gypidia (part), Dalman, 1828.' 



Teeebbatula (part), F. Buck, &c. (non Llhwyd.) 



Animal unknown. Shell oval, elongated ; valves nearly equally convex ; beak long, 

 produced, tapering and incurved at its extremity, hollow, and truncated in young speci- 

 mens by a small oval foramen ; no true area, a large concave deltidium partly surrounds 

 the aperture and extends to near the cardinal edge ; the umbo of the socket valve is con- 

 siderably incurved and concealed by and under the deltidium of the other valve ; the sides 

 of the beak as well as of the umbo become in some examples considerably deflected 

 inwards, producing deep, lateral, elongated, concave depressions, or pouches opening 

 externally, and not communicating with the interior; valves articulating by means of 

 teeth and sockets. In the interior of smaller valve, the calcified supports of the arms 

 form two conical spires, attached close to the socket walls by crural processes ;. surface 

 smooth or striated. 



Obs. The genus Uncites was proposed in 1828 by Defrance,'' and has been very 

 generally admitted, although its true character had not been established. Several authors 

 have endeavoured to define the section, but have evidently failed in their attempts. 

 M. d'Orbigny's diagnostic^ is essentially defective, since the beak was not, as he supposes, 

 entire, but hollow and truncated (at least up to a certain period of the animal's existence), 

 by a regular foramen, from which issued the pedicle of attachment : this point was proved 

 beyond doubt by a series of examples of all ages I obtained from Nimes, near Couvin 

 in Belgium. 



The internal details are not yet completely known. The muscular impressions remain 

 still to be ascertained ; but we are indebted to Professor Beyrich, of Berlin, for the 

 knowledge of the spiral supports, which he was so fortunate as to discover in a specimen 

 from Pafirath, figured, with his permission, in PI. VII, fig. 85.* The labial appendages 

 were not therefore simply attached at their origin, as supposed by M. d'Orbigny, nor does the 

 genus belong to the family of Bhjnchonellida, but to that of the Spiriferida, and should 

 be placed between Atrypa and Athyris (Retzia). The two singular lateral pouch-shaped 



^ Dalman proposed the term Gypidia, as a substitute for Pentamerus, Sow. ! his first example was the 

 T. gryphus of Schl., which is not a Pentamerus. Von Buch's synonymes of Uncites are very defective, as 

 are also all his observations on the species. 



^ Die. des Sciences Nat., Uncites gryphoides. 



'■■ Paleont. Fran9., vol. iv, p. 347, 1847. 



* I am indebted for the sketch of Professor Beyrich's specimen to my zealous friend M. Suess of 

 Vienna. 



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