1857.] KIRKBY — PERMIAN FOSSILS. 217 



posteriorly, and they have a surface finely granulated ; the lateral 

 areas, which are rather wide, are not strongly marked, and the lines 

 of growth are indistinct ; one or two wide grooved lines, commencing 

 at the posterior margin, run parallel to the lower margin, and are 

 continued faintly to the anterior dorsal region. The anterior plate 

 (fig. 13) is marked in a similar manner. The processes for insertion 

 are more prominent, narrower, and not so regularly arched as the 

 apophyses of C. Loftusianv.s (fig. 9). 



C Howseanus may he readily distinguished from the last-named 

 species, which is the only other Chiton found in the Permian rocks, 

 by the flatness and greater width of the plates, by the obscurity of 

 the lateral areas, and smoothness (want of strong lines of growth) of 

 the plates. The one or two grooved lines which follow the margin 

 are also characteristic. 



I have great pleasure in dedicating this species to Mr. R. Howse, 

 the author of an excellent ' Catalogue of the Fossils of the Permian 

 System of the counties of Northumberland and Durham,' and * Notes 

 on the Permian System of Durham,' &c. 



4. Lima Permiana. 



Lima Permiana^ King, Monogr. Perm. Foss. p. 154. pi. 13. fig. 4. 



It may be interesting to mention that this species, which Professor 

 King founded upon the knowledge of a single valve from Humbleton 

 Quarry, is not of rare occurrence at Tunstall Hill, and at Field House, 

 Ryhope ; from which localities I have obtained a very fine series of 

 specimens, completely illustrating and establishing the species*. 



This species, in common with all Limce, is characterized by a 

 hinge-area, by its being devoid of a notch under the front ear of the 

 right valve, and by the obliquity of its valves ; also by its hinge-area 

 being narrow, its ears small, and its valves smooth, which latter slope 

 gradually and shut close. 



5. HippoTHOA Yoigtiana, King, sp. PI. VII. figs. 14, 15. 

 Aulopora Voigtiana, King, Monog. Perm. Foss. p. 31. pi. 3, fig. 13. 



Prof. Kmg, in his ' Monograph of Permian Fossils,' gives a short 

 account of this fossil under the generic appellation of Aulopora. 

 His description and figures were from casts, no testiferous specimens 

 having been procured at that period, and were necessarily incomplete. 

 As I have been so fortunate as to find a perfect example of this 

 fossil, I have deemed it desirable to give a new figure, and to describe 

 the species afresh. 



The cells are oval, widest in front, produced or slender behind ; 

 they are placed rather near to each other, the connecting threads 

 being short and thicker than usual ; the aperture, which is situated 

 at the distal extremity of the cell, is rather large, circular, and pro- 

 tected by a smooth raised lip. 



* In the paper already referred to, Baron Schauroth describes and figures a 

 variety (subradiata) of this species. 



