93 PERMIAN FOSSILS. 



abundantly in the dark bluish Limestone near Nosterfield (Geo!. Soc, 2d series, vol. iii, 

 pp. 108, 119). As German, it is a widely-distributed and well-known species, being 

 found at Katterfeld, Schmerbach, Ilmenau, and Thalliter in the Kupferschiefer ; and 

 at Grafenheim, Konitz, Seissla, Kamsdorf, Ropsen, Gliicksbrunn, Wohlsdorf, Gera, 

 Ronneburg, and some other localities in the lower beds of the Zechstein. 



Productus umbonillatus. King. Plate XI, figs. 14, 15, 16, 17, 18. 



Productus umbonillatus. King. Catalogue, p. 8, 1848. 



— LATiROSTRA-TUS, Howse. T. N, F. C, vol. i, pp. 256, 257, 1848. 



Diagnosis. — Form subtriangular marginally ; plano-convex medio-longitudinally. 

 Large valve slightly convex ; scantily spinous ; with a shallow median furrow ; and a 

 small, pointed, more or less projecting umbone, which is flattened on the side adjoining 

 the hinge. Small valve nearly flat; with a prominent boss or cardinal muscular 

 fulcrum. 



I am not certain but this singular species will eventually be found to belong 

 to another genus, perhaps the Aulosteges of Helmerson, supposing it to be really 

 distinct from StropJialosia. The flattened space on that side of the umbone adjoining 

 the hinge has somewhat the appearance of an area (see the inferior side of the 

 prolongation [umbone], on the right side of fig. 18, PL XI) : but I cannot con- 

 vince myself that the part referred to is a true example of this structure : it also 

 possesses something like a closed fissure, which, however, I suspect is simply a notch 

 in the flattened (or area-like) space, caused by the cardinal boss pressing against it. 

 I can say with safety, that it is not furnished with any teeth ; it consequently cannot 

 be a Strophalosia. 



I have long considered this species to be distinct from Productus horridus, having, 

 in 1843, sent specimens under its present name (which was inserted in my MS. 

 Catalogue forwarded at the same time) to my valued friend M. de Verneuil. Productus 

 umhonillatus diff"ers from the latter species in its subtriangular form ; in the want of 

 ears ; in being considerably less convex ; and in having a small pointed beak, without 

 any incurvation. 



It is of rare occurrence in the Shelly Limestone at Tunstall Hill and Dalton-le- 

 Dale. As yet it does not appear to have been found in Germany, unless a fossil figured 

 by Geinitz (Versteinerungen, pi. vi, fig. 3) from Corbusen should prove to be the same 

 species. 



