544 ME. n. M. KYLE ON NASAL 



disappeared and one ventral only remains, the dorsal and anal are 

 coDtiniious roimd the tail, and the tail itself, carrying further 

 the change begun in Solea, has become " pseudo-diphycercal." 



These characteristics give the impression not merely of sand- 

 loving habits, but also that the animals bury their comparatively 

 heavy jaws and saout in the sand or gravel, whilst their long, 

 slender, and flexible tails move freely in the Avater. And in 

 this position they are more dependent upon their seuse of 

 smell than upon their powers of sight for the detection of their 

 food. 



Correlated with their mode of life iu some mysterious way is 

 the peculiar development of their lateral -line system. On the 

 right or blind side there is only one lateral line, on the left or 

 eyed side there are three of them — -one median, the other two near 

 the bases of the dorsal and anal fins. The median and dorsal 

 lines are continued on to the head, over the occipital region of 

 which a connecting branch joins the two. The median line gives 

 off' the usual branch over the preoperculum to the mandible, and 

 continues forw^ard almost to the anterior border of the head, 

 where it joins the dorsal line, which has followed the contour of 

 the head and is continued round the border to the curved snout. 



Pive specimens referred to this species, Cynoglossus semiJcevis, 

 have been examined, one of them in detail, the other four only 

 with regard to certain doubtful points *. Although these are 

 classed by Dr. Giinther as representatives of one species, the 

 individual examined in detail differs so markedly from the 

 other four that some systematists would not hesitate to make it 

 the type of a separate species or even genus, and the advisa- 

 bility of this will be considered when the facts concerning it 

 have been described. 



The characters already enumerated are shared by all five, and 

 in external appearance there is only one point of difference 

 between the divergent specimen and the others. In it. an acces- 

 sory branch of the lateral line passes backward from the ring 

 round the snout towards the posterior nostril between the eyes. 

 In the others this is absent. It is difficult to say what value can 

 be put upon this character. In many nearly allied species, e. g. 

 Synaptura., it is in exactly the same position ; and in many of the 

 North American flat-fishes (especially on the Pacific coast) 



* As these were registered specimens, I was very fortunate in having so 

 many to examine and in being pex-mitted to handle them so fully. 



