ICHTHYOLOGICAL NOTES 89 



therefore clear that the latter, in trying, to swallow a prey 

 rather too big for its capacity, failed in the attempt, while 

 the victim, in its struggles, passed its tail through the gill-slit 

 of the would-be devourer the encounter resulting in the 

 death of both. 



Cases of this kind do not seem to be very uncommon, and 

 it is interesting to find that, in many of those of which I have 

 heard, the tail of the captured fish bears a similar relation to 

 the gill-opening of the equally unfortunate captor as in the 

 instance described above. Professor M'Intosh, in his " Marine 

 Invertebrates and Fishes of St. Andrews" (p. 182, pi. viii. 

 Fig. i i), has recorded and figured a case in which a Broad- 

 nosed Eel, twenty inches in length, was in like manner " done 

 for " in attempting to make a meal of one of its own species ; 

 and here again the tail of the captured fish projects through 

 the narrow branchial opening of the larger one, while its 

 body, bent into a loop, projects from the mouth. Professor 

 M'Intosh has also informed me of other instances which he 

 has observed, in various species of fishes, since the publication 

 of the work which I have quoted. 



III. A FLOUNDER WITH THE EYES ON THE LEFT SIDE. 



Every one knows that in the family of Pleuronectidae or 

 Flat-fishes, both eyes are placed on one side of the head the 

 right or left, as the case may be ; the dorsal fin, however, 

 pursues its course in the middle line, and in many genera 

 passes actually in front of the region of the eyes. The 

 anatomical relations of the parts concerned, as well as the 

 embryonic development, show that this is effected by a bend- 

 ing over of the mesial plane of the head in the ocular region, 

 carrying the eye of the " blind " side along with it a torsion 

 in which the dorsal fin, advancing from behind, does not take 

 part. Young flat-fishes, on escaping from the egg, are quite 

 symmetrical, but after the transference of the eye has taken 

 place they swim on their side the blind side, which is 

 now the lower one, remaining white or pale in colour ; 

 while the ocular side, now the upper, becomes pigmented. 

 Interesting malformations or arrestments of development 

 are not uncommon, in which the turn of the eye has not 



