476 Survey of Fishing-Grounds, West Coast of Ireland, 1890-1891. 



The greatest actual variation in point-to-point measurement, however, is 

 certainly found in the relative positions of the vent, isthmus, and pelvic fins; and 

 this variation has no such developmental significance as has been demonstrated by 

 Giinther in the case of M. serridatiis {op. cit., PI. xxx., fig. 2 a). 



Fins. — An examination of a number of specimens shows a greater amount of 

 variation in this respect than seems previously to have been recognised. The 

 details of six specimens are here given : — 



A, 

 B, 

 C, 

 D, 

 E, 

 F, 



We have not found a specimen with as many as 14 rays in the first dorsal, as 

 set down by Giinther in his " Challenger" Report; and our formulae, in intro- 

 ducing the numbers 12 and 16 for the dorsal and pectoral fins, respectively, seems 

 to draw a certain additional resemblance to the formula given by Giinther for 

 3Iacrurus italicus, a form which that author shows so closely resembles Icevis that, 

 but for the condition of the teeth, the two would have been thrown together. 



The single specimen of M. italicus procured by the "Challenger" was only 

 5J- inches in length. Giglioli, the founder of the species, seems also to have had 

 only one small specimen.* On the other hand we do not find in Icevis more than 

 9 rays in the ventral fin. 



Scales. — The scales of our smallest specimens are somewhat irregularly 

 arranged, are very deciduous, and bear relatively lung spinelets arranged in two 

 or three very irregular rows. The condition in the adult is quite distinct (fig. 3«.) 

 The scales of the young examples are apparently very similar to those described 

 for M. italicus. 



Size. — So far as we know, the largest recorded size is that of our largest 

 specimen — 21^ inches or 54'5 cm. 



Abdominal Viscera, ^'c. — In the specimens examined the viscera seemed remark- 

 ably small, a considerable space remaining even after allowing for an unusual 

 amount of shrinkage. The black scaleless depressions already mentioned have on 

 their inner surfaces strong muscular attachments for the rectum and the generative 

 ducts. The rectum comes almost directly downwards, while the generative ducts 

 pass forwards and downwards from the posterior extremity of the abdominal 

 cavity where the curved reproductive organs are situated. Both are borne by a 



* "Challenger Reports," vol. xxii., p. 141. 



