164 NOTES ON AUSONIA COCKSII. 



In order to establish the differences existing between these two 

 solitary examples, it will be only necessary for me to furnish a 

 brief summary of the measurements and markings of my example, 

 and then to contrast them with some few of those which strike 

 me as peculiar in Mr. Couch's. They run as follows : — length, 4 

 feet, circumference 3 feet, depth 14 inches, thickness 7| inches, 

 weight 128 lbs. Sex male. Shape acutely ovate, thickest across 

 the pectoral fins, gradually tapering thence towards the tail. Sur- 

 face of the body of a rich metallic silvery hue, pervaded throughout 

 by a coating of the richest scarlet, most brilliant above the lateral 

 line, and gradually becoming fainter towards the belly and anal 

 fins. Head large and of most peculiar shape, the frontal portions 

 of the cranium having a completely hydrocephalic appearance. 

 Mouth small and situated about midway between the vertex and 

 the lowermost point of the gill coverts. Lips firm, fleshy, and 

 equal. Gill coverts of intense brilliancy and very firm, posterior 

 reaching to within two inches of the insertion of the pectoral fin. 

 Eye situated about 4 inches from the gape, and 5f from the outer 

 margin of the gill covert ; measuring in diameter one inch and 

 three quarters, margin of orbit narrow, having the appearance of 

 a dark circle. Iris divided by concentric rings ; the first silver-grey, 

 second scarlet, third silver-grey, fourth deep blackish grey, and the 

 fifth narrow silvery white. Pupil moderately large, circular, and 

 black. Lateral line very faint, disappearing entirely before reaching 

 the pectoral fins. Back broad, firm, and fleshy. Pectorals deep 

 scarlet, having 17 stout fin rays, and measuring 10| inches in 

 length ; bluntly triangular in shape. Dorsal fin measuring 1 1 

 inches ; first spine 9 inches in length, strong, curved, and sharp 

 pointed ; the others 1 3 in number, only about an inch in length, 

 and, like the first, of a bright scarlet colour ; membrane cobalt 

 blue. From first spine to gape 27 inches ; from same spine to 

 centre of outer margin of caudaL^n 23 inches. Anal fin 11 inches ; 

 first spine scarlet, similar in shape to that in dorsal, and 8 inches 

 in length ; the remainder 1 3 in number, all stout, an inch in 

 length, and similar in colour; membrane cobalt blue. At the 

 termination of the dorsal and anal fins the extremity of the body 

 becomes rou.nded to the insertion of the caudal fin, and is armed 

 with three cartilaginous ridges on either side, arranged in an 

 arrow-headed shape ; the centre one four inches in length, with a 



