Prof. W. King's Notes on Permian Fossils. 261 



Productus aculeatuSy according to the figures given of it by 

 De Koninck, seems to be a closely related form, the principal dif- 

 ference being, that the small valve of the present fossil is not 

 radially costulated. P. granulosus appears to be another allied 

 form ; as is also P. scabriculus. In some of these species the spine- 

 bases are elongated, and extended considerably in front of the 

 spines, which are thereby made to appear as if directed back- 

 wards or towards the hinge : the same character is exhibited in 

 P. GeinitzianuSf but it appears to have escaped the notice of 

 De Koninck ; or perhaps his specimens did not possess it. The 

 resemblance between P. Geinitzianus and Strophalosia [Orthis) 

 excavata clearly led Geinitz to conclude both forms to be iden- 

 tical; but in the latter species the spines are finer, decidedly 

 more numerous, and strikingly arranged in quincunx. 



Perceiving no trace of teeth or of an area in the example I 

 have examined, which is about an inch in width, I am led to con- 

 clude that the species is a true Productus. 



De Koninck states that it is a " very rare species/' His spe- 

 cimens are from the Zechstein in the neighbourhood of Milbitz. 

 The specimen figured is from Ropsen. It has not yet been made 

 known as occurring in any British formations. 



Productus SchaurothianuSy n. sp. PI. XII. figs. 3, 4 & 5. 



Lately breaking up a few fragments of dark-coloured Zech- 

 stein from Ropsen, I was agreeably surprised to find a few spe- 

 cimens of a small shell, which, at first sight, from its possessing 

 an irregularly impressed or truncated umbone, appeared to me 

 to be a species of oyster. A closer examination, however, con- 

 vinced me that it was a Productus, altogether unlike any I was 

 acquainted with. I therefore embrace the present opportunity 

 of describing it and of dedicating it to my friend Baron von 

 Schauroth, who has within the last few years contributed much 

 towards elucidating the palaeontology of the German Permians. 



Diagnosis. — General form irregularly hemispherical. Large 

 valve irregularly and strongly convex; having a distinct median 

 depression; and marked with longitudinal costules, occasionally 

 dichotomous ; its umbone deeply and irregularly impressed or 

 truncated. Small valve flattish or slightly concave; wrinkled 

 parallel to its free margin ; and marked with nearly obsolete 

 radiating costules. Hinge-line about (?) half the width of the 

 valves. 



Productus Schaurothianus has much the aspect of some of the 

 so-called Thecidiums of the Jurassic system, such as T. Deslong- 

 champsii, David., which has a somewhat similar truncation of 

 the umbone. With this remarkable peculiarity, it is quite an 



