Correspondence — Mr. T. P. Barkas. 43 



UNUSUAL FORMS OF CTENOPTTCHIUS. 



Sir, — Among the numerous fossil remains wliich I have recently 

 obtained from the shale overlying the Low Main Coal-seam in 

 Northumberland, there are two peculiar forms of C'tenoptycMus, which 

 seem worthy of being illustrated and recorded in your pages. 



The two species, Ctenojytychius pectinatus, and C denticulatus are 

 very abundant, but they are of the usual forms, with serrated upper 

 edges, the serrations varying from eight to upwards of twenty in 

 number, and the roots extending downwards from the body of the 

 tooth or tubercle connected with the serrated edge. 



Teeth of CTENOPiYcunjs. 

 Fig. 1. ""^ 



Kg. 2, 



Fig. 1. With 33 Serrations (twice natural size). 

 Fig. 2. With 17 Serrations (three times natural size). 



The two specimens to which I desire to direct special attention 

 (see Woodcut) are the only two I have obtained with lateral in- 

 stead of perpendicular extensions. There is in the two specimens 

 an entire absence of the root-like processes which ordinarily cha- 

 racterise CtenoptycMus. The only extension from the serrated 

 bodies of the teeth proceeds from one side, and the teeth present the 

 appearance of miniature combs, with long, slender solid handles. 

 I shall best convey an accurate idea of their sizes, forms, and general 

 appearance by the annexed outline sketches. (See Woodcut above.) 



I have just learned that several specimens in my collection from 

 the Northumberland Carboniferous strata, which I have been ascribing 

 to MegalicJithys, are in reality Parahatrachus, a frog-like reptile, 

 which was originally discovered in the Glasgow Coal-measures, and 

 was described by Professor Owen in the Geological Journal, vol. ix. 

 The glazed and punctured character of the head-plates bear a re- 

 markable resemblance to those of Megaliclithys ; their forms, how- 

 ever, differ considerably. T. P. Barkas. 

 Newcastle-on-Tyne, Dec. 5, 1868. 



ON A NEWLY-DISCOVERED LONG-EYED TRILOBITE FROM 



DUDLEY. 



Under the above heading, I published an Ai'ticle in the Geological 

 Magazine for November last, p. 489, in which I described a speci- 

 men of Galymene BlumenhacMi having long eye-stalks, obligingly 

 lent me by Mr. E. HoUier. 



On Nov. 3rd I received a note from Mr. Charles Ketley, of 

 Smethwick, informing me that he knew the specimen, and that the 

 so-called eye-stalks were, in his opinion, only parts of the under- 

 side of the head-margin of another Trilobite in contact icitli, but not 

 apart, of the specimen described. 



