1879.] ON TRIGLA PCECILOPTERA AND TRIGLA HIRUNDO. 1/9 



10. On the Identity of Trigla pceciloptera and T. hirundo. 

 By Francis Day, F.Z.S. 



[Eeceived February 17, 1879.] 

 (Plate XVIII.) 



While at the Westminster Aquarium in the month of October last 

 year, n v attention was drawn to some small but beautiful Gurnards 

 that h;.;l recently been obtained from Southend. The colours on 

 the inm i- side of their pectoral fins did not coincide with that shown in 

 any British example ; and the presence of a large, black, oval blotch, 

 covered with light blue spots, seemed to render it probable that they 

 might be t'e "Little Gurnard" {Trigla pceciloptera) — a species which 

 neither Y:. rell nor Couch were so fortunate as to obtain'. I therefore 

 asked Mr. arrington, the naturalist to that establishment, to preserve 

 any examph i that died, in order that I might have the opportunity of 

 ascertaining, first, if they belonged to the species I supposed, and, se- 

 condly, if sucli specimens were or were not the young of another form. 

 I have now to record my thanks to INIr. Carrington for six excellent 

 examples of the "Little Gurnard " (varying from 2'0 to 9'8 inches in 

 length), which, so far as I am aware, has not previously been re- 

 corded from the waters of Great Britain, although a fish two inches in 

 length has been reported to have been captured in Ireland, but, as I 

 shall presently how, was either wrongly identified or erroneously 

 described. 



This fish has been recorded in several works (Cuv. & Val. iv. p. 

 47 ; Thompson, P.Z.S. 1837, p. 61 ; Yarrell, Brit. Fishes, i. p. 49 ; 

 Demid. Voy. Russ. merid. iii. p. 375 ; Guichen. Explor. Alger. Poiss. 

 p. 39 ; Giinther, Catal. ii. p. 203 ; Couch, Brit. Fishes, ii. p. 36, 

 pi. Ixx. f. 2?). Some of the authors have personally examined speci- 

 mens ; others havt -opied their descriptions from previous writers ; 

 but all coincide in the statement that it has not been taken upwards 

 of 4 inches in lenstl;. 



I do not propose giving a detailed account of the species, as such 

 may be found in Cuv. & Val. To what is there recorded I will, how- 

 ever, add that it has ten csecal appendages, and that the number of 

 spined plates along the bases of the dorsal fins is from 25 to 26 on 

 either side, a not Tuicommon number in the species of this genus. 



At 51 inches in length the various spinate projections on the head, 

 shoulder, and along the bases of the dorsal fins become more blunted, 

 the colours on the body are not so vivid, while the oval black blotch 

 with blue spots on the inner side of the pectoral fin is more decidedly 

 blue, covered with white spots. If an example, coloured as in T. 

 hirundo, of the same size is placed alongside, scarcely any differences 

 are perceptible ; the number of spinate elevations along the bases of 

 the dorsal fins, of the fin-rays, of the rows of scales, and the propor- 

 tions of the various parts of the body are the same. 



^ Yarrell gave a figure of this fish in his second edition from a French drawing. 



12* 



