2 



BRITISH FOSSILS. 



length. The greatest depth is two inches and a half. The head is 

 proportionately smaller than in the other species of Megalurus, 

 and the posterior edge of the opercular flap more angular. The 

 dorsal line is nearly straight, while the abdominal line has a con- 

 siderable downward curvature. These lines are nearly parallel in 

 Megalurus Damoni, and in Megalurus lepidotus the dorsal line is 

 more curved than the abdominal line. Thirty-five vertebrae are 

 preserved, of strong osseous texture. The length of each is rather 

 greater than the diameter. The peripheral pits are deep and 

 strongly marked, but the size of the intervertebral cavities cannot 

 be ascertained. The processes of the anterior vertebrae are short, 

 thick, and curved, those of the posterior part of the column straight, 

 long, and slender. The scapulocoracoid arch appears to have been 

 slight, and the pectoral fins of moderate size. The component 

 rays are subdivided transversely into a great number of ossicles, a 

 structure which must have given great pliability to the fin. The 

 ventral fins are small, but strengthened by a thick anterior ray to 

 each fin^ having considerable curvature at its pelvic extremity. 

 The dorsal fin is situated over the ventral fins, and extends as far 

 backwards as the insertion of the anal fin. The three or four anterior 

 rays are short, strong, and pointed, the succeeding rays are long, 

 dichotomous, and articulated transversely at short intervals. The 

 number of rays composing the fin was not less than seventeen, and 

 these are supported on a like number of interapophyseal ossicles 

 deeply inserted in the integumentary tissues. The position of the 

 anal fin is seen by a slight impression of the anterior rays in the 

 matrix of the specimen, but an unfortunate fracture has removed 

 the fin itself The scales more nearly resemble those of Megalurus 

 lepidotus than those of Megalurus Damoni; they are, however, 

 too imperfect to be accurately examined. I have named this 

 species Megalurus Austeni, in recognition of the labours of the 

 Rev. John Austen in working out the stratigraphical details of the 

 Purbeck beds. 



Locality. — The specimen figured and described was found in a 

 quarry of Purbeck stone in the neighbourhood of Swanage, and is 

 now in my possession. 



DESCPaPTiON or Plate 9. 

 Fig. 1. Megalurus Austeni, size of nature. 



P. DE M. Geey Egerton. 



April 20, 1857. 



