220 E. D. Wellhum—Fish Fauna of Millstone Qrlt. 



British Museum (Natural History), Cromwell Eoad, and consider 

 that the above fish should be placed in this genus, but the crushed 

 condition of the specimen renders the determination of its species one 

 of some difficulty, and it appears best to leave this question for later 

 consideration. Besides the above I have found several detached 

 spines of this fish. 



Form, and loc. : D Shales, Middle Grits, Summit. 



ICHTHYODOKULITES. 



Genus ACONDYLACANTHUS, St. John & Worthen, 1875. 



Acondylacanthus, sp. ? 



One spine shows the characters of this genus, but it has suffered 

 so much from erosion that the determination of its species is im- 

 possible. 



Form, and loc. : D Shales, Middle Grits, Summit. 

 Genus EUCTENODOPSIS, gen. nov. 

 Euctenodopsis, sp. nov. 



This Ichtbyodorulite is most interesting, and at first sight might 

 easily be mistaken for a specimen of the nearly allied genus Euctenhis, 

 Traquair. However, on a more careful examination it is at once 

 apparent that it does not agree with the generic diagnosis of that 

 genus, as given by Dr. Traquair,' in the important fact that, instead 

 of having one end (the proximal) " rounded or blunt," this portion 

 is drawn out and forms a more or less spatulate extension, which 

 appeal's to differ somewhat in texture from that of the other portions 

 of the spine. I say spine, as I consider the Ichthyolite was a dermal 

 defence of some Selachian fish, and that the spatulate extension was 

 its point of insertion. Although the spine is narrower and more 

 elongated than any of the known species of ^udenius, still, in many 

 of its characters it agrees with that genus, being more or less 

 elliptical in form, laterally compressed, one side concave, the other 

 convex, one extremity produced into a long narrow extension, and 

 the convex margin is divided in a comb-like manner into a number 

 of closely arranged blunt-pointed denticles. 



On account of the above-mentioned peculiarity — the spatulate 

 extension at its proximal end — I venture to place the spine in 

 a new genus, for which I propose the name Euctenodopsis, and, 

 on account of its narrow and elongated form, with the specific 

 designation tenuis. 



Form, and loo. : D Shales, Middle Grits, Summit. 



Family EHIZODONTID^. 



Genus STREPSODUS, Young, 1866. 

 Strepsodus sulcidens, Hancock & Atthey, 1870-1871. 

 Mr. Aitken - in his paper refers to a tooth of Strepsodus. Mr. John 

 Ward, F.G.S., of Longton, who has seen the specimen, informs me 

 that it was a tooth of Strepsodus sulcidens. 



Form, and loc. : D Shales, Middle Grits, Wadsworth Moor. 



I Geol. Mag., Dec. II, Vol. VIII (1881), pp. 36-334. 

 - Aitken, op. cit. 



