IN THE SOUTH- WESTERN DISTRICT. 181 



importance. It is a common, perhaps a normal feature of the embryo 

 of Arnoglossus, but it is not constant, even in the species of that genus. 

 In typical specimens of Sp. F or xii. it is extremely well marked, but the 

 Topknot eggs which I have seen at Plymouth do not lend themselves to 

 discrimination by this character. Two of them, and it is necessary 

 to remark that these two ('OO, "Ol, 0'9, -13) are the smallest of the 

 series, have the reticulo-papillate epidermal character most strongly 

 marked, but the rest are variable. Some have the skin practically 

 smooth. In others it is more or less papillate, with an approach in 

 some instances to reticulation. Moreover, the typically reticulo- 

 papillate condition was observed as an exceptional, perhaps a 

 pathological feature in a species which does not appear from the 

 characters of the larva to be a Pleuronectid {vide the egg and larva 

 temporarily assigned to a Gadoid, p. 145). 



Apart from the papillation of the skin, I now believe that the 

 various early Topknot larvie, which have been described from tow- 

 net ova, cannot be distinguished by characters of pigment and 

 conformation. Those which have come under my notice at Plymouth 

 seemed to be referable to my Species x., xi., and xii., but, on the other 

 hand, they appeared capable of bridging over the differences which 

 I had supposed sufficient to separate those species. Species x. was 

 originally supposed by myself to have a Trigloid affinity, on account 

 of the rather precocious development of the pectoral fin and a certain 

 Trigloid character of the pigment of the marginal fins. I am now 

 convinced of error in this respect, and it appears reasonably certain 

 that all our British Trighe have much larger eggs. 



An inevitable want of continuity in our tow-netting operations 

 during the period when these eggs occurred, seems to me to greatly 

 prejudice any discussion based on the comparative sizes of the eggs 

 taken. As to the general question of the determination, by the 

 characters of the vitelligerous larva, of the eggs of the several species 

 of Topknot, I do not think it is possible, as yet, to pronounce a 

 definite opinion. The single larva which I was able to rear from 

 artificially fertilised ova of P. unimaculatus seems to me to suggest 

 that some of the ova which have been described under Sp. F belong 

 to that form. Further, it would appear that the reticulo-papillate 

 larva is perhaps more commonly hatched from the smaller of the 

 eggs which may safely be assigned to Topknots. M'Intosh and 

 Master man deal with the egg and larva F under lih. pmidatus, but 

 it does not appear that they wish to definitely identify them with 

 that species. It seems at least possible that the reticulo-papillate 

 condition may be more or less pathological ; and if, as I suppose to 

 be the case, the smaller spawning members of a species give rise to 



