38 MR. J. COUCH ON A NEWLY DISCOTERED BBITISH FISH. 



IV. EvABNE. To this genus he refers no. 3 of the genus 

 Antinoe, p. 192, the Polynoe impar of Johnson. 



V. Lanilla. To this genus he refers no. 1 of the genus 

 Antinoe, p. 192, the Polynoe Icevis of MM. Audouin & Edwards. 



VI. MELiENis, and VII. Euceantia. Of these two genera no 

 species had been described previously. 



VIII. Alentia. To this genus Malmgren refers no 9 of the 

 genus Halosydna, p. 187, the Polynoe gelatinosa of Sars. 



IX. Enipo, and X. Nemidia. These genera approach the re- 

 stricted genus Polynoe; but no species had previously been 

 described. 



Some Account of a newly discovered British Fish of the Family 

 GadidcB and the genus CoucJiia. By Jonathan Couch, E.L.S., 

 &c. 



[Read Nov. 16, 1865.] 



The genus Ooucliia was formed by Mr. W. Thompson, and has 

 been adopted by Dr. Giinther, as separated from that of Motella 

 or the Eocklings by the more moderately lengthened body of the 

 species, which is also compressed, and by the silvery and brilliant 

 appearance of the sides. In fact, in their general proportions 

 the fishes of this genus are as different from the Eocklings as, 

 among their kindred the other Gadidce, the Pollack and Whiting 

 are from the Ling ; while their manners also, so far as they 

 are known, are as different as their shape. And yet, in some 

 of the more prominent particulars of their organization, there 

 exists a similarity between the Motellce and Couchi<s, which is 

 the more remarkable as it consists of a relative gradation in the 

 species of each, which is only to be traced throughout by the dis- 

 covery of one, of which a notice is now presented to the Linneau 

 Society. 



As there is a species of Motella which is characterized by the 

 presence of four prominent barbs placed in pairs on the front of 

 the head, with a barb dependent also from the lower jaw, so we 

 find in the best-known, and probably most widely spread, of the 

 genus Concilia, the Mackerel Midge {G. glauca), a similar confor- 

 mation, together with a characteristic ciliated membrane situated 

 in a chink in advance of the dorsal fin ; which membrane certainly 

 is not itself a fin, but an organ of sensibility which is in its most 

 lively motion when the proper fins are at rest. But long before 



