CONTRIBUTIONS TO THE STUDY OF VARIATION. 



BY JAMES HORNELL. 



Series I. — a. Sexual colour divergence in Labrus mixtus. 



b. Duplication and origin of the operculum in Serpula. 



c. Anastomosing of muscle bands in Salpa. 



I. Sexual colour divergence in Labrus mixtus. 



THE Labrus mixtus of Linnseus, and the L. trimaculatus of 

 Pennant, are by no means rare on the Jersey coast. Yearly 

 a fair number are caught during the warmer months, especially in 

 the more deeply sunk lobster pots. Apparently they do not come so 

 close inshore as the other Wrasses. 



These fishes differ so immensely in colour that they are recorded 

 as different species, while at the same time, the fact that they agree 

 closely in size, habits, contour, and anatomy, has given rise to the 

 strong suspicion that they, in reality, represent the different sexes of 

 the same animal. Dr. Gunther, among others, has formulated this 

 opinion, and undoubtedly it is correct, for the sole divergence — 

 colour — I have recently noticed to vary in a manner calculated to 

 remove all doubt as to such relationship being the true explanation. 



Than L. mixtus, called here " coucou " universally by the native 

 fishermen, there is probably no more gorgeously bedecked British 

 fish. So bizarre and gaudy is it indeed, that the taxidermist, who, 

 with scrupulous fidelity, reproduces the crude and glaring tints in 

 their full brightness, is apt to have his work eyed askance, and to 

 receive as scant courtesy as did the traveller's tales of Bruce on his 

 return from that memorable pioneer Abysinnian journey. Bright 

 orange red predominates, streaked by some three longitudinal vivid 

 blue bands ; several blue or purplish markings and blotchings adorn 

 the head, in which glistens — a very jewel — the bright crimson eye. 

 The large dorsal fin is orange and red in varying patterns — some- 

 times a margin of blue specially strong at the hinder end — more 

 rarely the anterior part blue, the hinder orange. Then the tail is a 

 marvel of colour, the blue usually disposed as a sharply defined 

 edging. 



