PERMIAN FOSSILS FROM DURHAM. 201 



Humbleton Quarry, is not of rare occurrence at Tunstall Hill, 

 and at Field House, Ryliope; from which localities I have ob- 

 tained 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 VoiGTiANA, Klng^ sp. PI. XII. figs. 14, 15. 



Aulopora Yoigtiana, King^ Monog. Perm. Foss. ^\.pl. 3. Jig. 4. 



Prof. King, in his " Monograph of Permian Fossils," gives a 

 short account of this fossil under the generic appellation of Aulo- 

 2)ora. His description and figures were from casts, no testiferous 

 specimens having been procured at that period, and were neces- 

 sarily incomplete. As I have been so fortunate as to find a per- 

 fect 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 situ- 

 ated at the distant extremity of the cell, is rather large, circular, 

 and protected by a smooth raised lip. 



My specimen is not much branched ; but the branches always 

 arise from the anterior portion of the cell at an obtuse angle. 



This fossil is undoubtedly a Bryozoon ; and, as the genus Aulo- 

 pora is stated by MM. Edwards and J. Haime to be only the 

 young stoloniferous base of a Syringopora, I have, after an atten- 

 tive examination of its affinities to existing genera, placed it in 

 the genus Hippothoa, to which it bears a strong resemblance 

 and evidently close relation. 



The specimen figured is from Tunstall Hill, and is attached to 

 the external surface of a Terebratula elongata.\ 



* In the paper already referred to, Baron Schaurotli describes and figures a variety (subra- 

 diata) of this species, 

 t See Note 4. 



