Holt and Calderwood — Report on the Rarer Fishes. 



487 



haul made during the Survey occurred nearly due west of Mizen Head (see Chart, 

 " Sci. Proc," vii., pt. 4). 



Griinther {loc. eit.) has given a careful description of R. Boscii, calling attention 

 at the same time to the work of earlier authors, of whom VincigTierra and Kolam- 

 batovie are cited as having been the first to satisfactorily define the differences 

 which separate it from R. megastoma. The author remarks that R. Boscii raaj be 



Fig> 6. — Rhomliia Boscii. 



recognized at a glance by its enormous eyes, and, in support of this statement, 

 cites the dimensions of a specimen of each species. 



The only specimen of R. Boscii at our disposal is one from the Mediterranean, 

 in the Science and Art Museum, at Dublin, a photo-outline of which is given in the 

 accompanying figure. It measures 26"25 cm. in total length, and, on comparison 

 with a Survey sail-fluke of exactly the same total length from deep water, the 

 greater size of the eyes in R. Boscii is not apparent. The two fish, in fact, have 



Fig. H Rhotnlus megastoma. 



eyes of the same size ; though, relatively to the size of the head, the eyes are 

 somewhat the larger in R. Boscii, in which species, as Griinther remarks, the 

 length of the eye is one-third of the length of the head. In the specimen of 

 R. megastoma the length of the head is about 3j times as great as that of the eye. 

 In spite of this resemblance, the two fish can be recognised at a glance as distinct, 

 without appeal to the difference in the fin-rays. The anterior profile is much 

 more abrupt in R. Boscii, the upper and lower margins of the head forming a right 

 angle at the anterior extremity. The angle so formed in R. megastoma is much 

 more acute. The scales are conspicuously larger, and the bight of the lateral line 



