350 Dr. A. Giinther on the British Species of Mugil. 



wider than the posterior (see figure, pi. 309, in Cuv.et Val., which 

 is copied by Parnell, Fishes of the Frith of Forth, pi. 28) ; in 

 M. septentrionalis the prseorbital is very obliquely truncated, so 

 that its posterior angle is pointed, whilst the anterior is very 

 obtuse and rounded (see Yarr. Brit. Fishes, 2nd edit. i. p. 243, 

 lateral view of the head). 



3. The pectoral fin is much longer in M. chelo ; it extends to 

 the thirteenth scale of the lateral line — that is, nearly to the origin 

 of the dorsal fin, which is above the fourteenth or fifteenth scale, 



4. The whole of the caudal portion is shorter in M. chelo, so 

 that the origin of the spinous dorsal fin is nearer to the root of 

 the caudal than to the end of the snout. 



These points will suffice to show that M. chelo and M. septen- 

 trionalis are two distinct species*; and we must therefore be 

 careful in using for their determination figures which were 

 executed when the species had not been distinguished. 



a. Bonaparte's figure in the * Fauna Italica ' is taken from 

 M. chelo ; but the outlines of the prseorbital are incorrect. 



h. Cuv. et Val. Hist. Poiss. pi. 309 represents the head of the 

 true M. chelo. 



c. Yarrell, Brit. Fishes, 2nd edit. i.p. 241, figure of the entire 

 fish, is a copy from Bonaparte's Mugil chelo, and does not re- 

 present the British species. 



d. Yarrell, I.e. p. 243. The lateral view of the head is 

 original, and taken from a British sTpecimen of M. septentrionalis ; 

 whilst the view from below, again, is a copy of Bonaparte's Mugil 

 chelo. 



e. Parnell (/. c.) copies the head of M. chelo from the ' Hist. 

 Nat. des Poissons.' 



This species is not confined to the British coasts. Professor 

 Nilsson, who also takes it for M. chelo, Cuv., has given an ex- 

 cellent description of it, from which it is evident that the thick- 

 lipped Mullets of Scandinavia are identical with the British ; so 

 that M. septentrionalis appears to be common to the northern 

 shores of Europe, whilst M. chelo frequents the southern. 



I do not pretend to give this as a complete account of the 

 British Grey Mullets. The present paper contains only the 

 result of observations made on the materials which I have found 

 in the British Museum, and on a collection which the Keeper 

 of the Zoological Department, Dr. Gray, has enabled me to 

 make during the first half of the month of March ; and I feel 

 fully convinced that, by continued accurate investigations, not 



* A difference of minor importance is that M. chelo has seven, M. sep- 

 tentrionalis five pyloric ap]jendages. 



