Holt and Caldeewood — Report on the Rarer Fishes. 489 



Arnoglossus laterna, 



Platophrys laterna, 

 Pleuronectes arnoglossus. 



. GiJNTHEE, "Proc. Zool. Soc," 1890, p. 40. 



. Cunningham, " Proc. Zool. Soc," 1890, p. 540, 



. Smitt, " Hist. Stand. Fisk.," ed. ii., p. 428. 



. Fleming, "Brit. An.," p. 197. 



. TuRTON, "Brit. Fauna," p. 97. 



. Bonaparte, " Faun. Ital. Pesc." 



. Jenyns, " Man.," p. 465. 



. Canestrini, "Arch. Zool.," i., p. 14. 



. Yarrell, "Brit. Fish.," ed. iii., i., p. 644. 



Diagnosis of Species.— D. 84-102. A. 64-81. Vert. 39-42. Reaches a 

 length of 20 cm. 



Scales of moderate size, very thin and deciduous, their free margins ciliate on 

 the ocular, smooth on the blind side, rather angular in large males. Lateral line 

 with an almost rectangular curve anterioi'ly, its scales not pierced by sensory tubes 

 on the blind side. Teeth of equal size. 



The length of the head about 4^ times, and the greatest height of the body, 

 situate about opposite the extremity of the pectoral, about 2\ times in the total 

 length, exclusive of the caudal. Anterior profile rather obtuse, especially in large 

 males ; jaws subequal anteriorly, the length of the maxilla of the ocular side about 

 3 times in large males and young examples of either sex, about 2\ times in large 

 females in the length of the head. The length of the eye about 4 times in large 

 males, about 5 times in large females in the length of the head. Eyes separated 

 by a very narrow, scaleless, bony ridge, the lower being in advance of the upj)er. 



Dorsal and anal fin continued to the root of the caudal. In specimens 

 exceeding about 13 cm. the second to the sixth dorsal rays become prolonged, the 

 longest, in large males, being nearly equal to the length of the head. In females 

 the longest ray does not exceed one-third of that measm-ement. Extremities of 

 these rays free and filamentous. 



The pelvic fin of the ocular side occupies the whole ventral edge from the 

 isthmus to the anus. The pelvic rays become prolonged in large specimens, 

 especially in males. Ocular side brown, with darker patches and mottliugs. A 

 black spot on the pelvic in males. 



As is well known, the separation of A. laterna and A. lophotes was based, by 

 the various authors -who studied these two forms, chiefly upon certain differences 

 in the length and character of the anterior dorsal and the pelvic rays, in the fin- 

 ray formula, and in the proportions of the eyes and upper jaw. That most of 

 these differences were merely sexual was first asserted by Mr. Cunningham {loc. cit.) 

 in 1890, the author being led to this conclusion by the examination of a considerable 

 number of examples of both forms taken on the S.W. coast of England. 



TKAUS. EOT. DTJB. SOC, N.S. VOL. V., PAET LS. 3 Z 



