48 SALMONID.!;. 



strikingly different appearance which has procured for them a dis- 

 tinct vernacular name, Twh-y-daiJ. They are comparatively shorter 

 than the Sewin, brownish red, or silvery with a reddish hue, and 

 sparingly spotted with black; the dentition of the males is exceed- 

 ingly strong, and the vomer is always armed. with some of the teeth 

 of the longitudinal series. 



However, the specimens vary much, thereby indicating their 

 hybrid origin, and we shall give descriptions of several forms ob- 

 served. 



These Welsh specimens are produced by the Sewin and that form 

 of the Uiver-Trout which is named S. fario ausonii. 



A very valuable collection of Salraonoids which we received from 

 the Copenhagen Museum, contained several specimens which, being 

 intermediate between Salmo cambricus and S. fario gaimardi, and 

 extremely similar to the hybrid from Wales just described, are 

 evidently of a similar origin. Such hybrids may have been fre- 

 quently regarded and described as Salmo eriooc. 



The number of vertebrae is 58 in Welsh, and 59 in Danish speci- 

 mens, atid that of the pyloric appendages 41, 44, 45 or 46. 



* Specimens from So^'tJi Wales. 



a. Male, 19| inches long. Ogmore Kiver, Glamorganshire. Pre- 



sented by R. Franklin, Esq. The vernacular name of this form 

 is Twb-y-dail. 



b, c. Males; 23 inches long : sldns. Glamorganshire. From Mr. 



Yarrell's Collection. 



d. e-f. Male and female, 1 6 and 19| inches long. Rhyraney. Pre- 

 sented by the Rev. Aug. Morgan. 



g-lu Females, 14 and 10 inches long. Taliaris. Presented by 

 W. Peel, Esq. These specimens were kept in a freshwater 

 pond for more than a year, and are sterile. 



?. Male, 13 inches long. RhjTuney. Presented by the Rev. Aug. 

 Morgan. 



I: Male, 11 inches long. Towey, South Wales. Presented by Dr. 

 A. Giinther. 



/. Male, 9 inches long, bred in a pond at Mackin. Rhymney. Pre- 

 sented by the Rev. Aug. Morgan. Caught May 18th. 



m-u. From 6 to 8 inches long. Towey. Presented by Dr. A. 

 Giinther. 



p. Many specimens, from 6 to 12 inches long, a part of which are 

 immature. River Usk. Presented by J. Lloyd, Esq. jun. 



q. Several specimens, from 4 to G inches Tong. Rhymney. Pre- 

 sented by the Rev. Aug. Morgan. 



r. Six inches and a half long. River near Goodwick, Pembroke- 

 shire. Presented by Hugh Ch. Owen, Esq. Caught in the 

 middle of March. 



s. Seven inches long. River Cleddan, Pembrokeshire. Presented by 

 Hugh Ch. Owen, Esq. Caught in the middle of March. 



