114 ACANTnOPTERYGII. 



On comparison, the largest G. nigcr, Cuv. and Val., 3 inches 2 lines 

 long, and the G. Britannicus, 3 inches in length, present the following ap- 

 pearances : — 



Viewed from above, the head is more equable in breadth in G. Britannicus ; 

 in the other it approaches more to a conical form. When placed on the side, 

 the G. niger is rather the deeper, carrying greater breadth to the base of the 

 caudal fin ; the scales are much smaller in G. niger, yet the cilia on their 

 margins are longer than in the other : from some of the scales being wanting, 

 their number cannot be accurately given ; but, reckoned from the opercle in 

 a straight line along the middle of the body — for the lateral line is inconspicu- 

 ous in both species — to the base of the caudal fin, there are about 10 more in 

 G. niger than in G. Britannicus ; about 45 in the one and 55 in the other may 

 be mentioned as an approximation : pecten-like strias * on the scales of both 

 species. In G. ?iiger the outer row of teeth in both jaws is considerably the 

 largest, and they differ entirely in form from those of G. Britannicus, this 

 being the most obvious differential character between the species ; of the 

 large hooked teeth, there are about 16 in the outer row of each jaw; no teeth 

 apparent either on vomer or tongue ; f in addition to the very ninnerous card- 

 like teeth in both jaws of G. Britannicus, the anterior part of the vomer is paved 

 with them; on the tongue none are apparent. J The dorsal fins contiguous in 

 both, the 2iid D. is obviously higher than the 1st in G. niger than in G. Britan- 

 nicus, as in the latter the two or three longest rays are equal to the general 

 length of those in the 2nd D., a size which they do not attain in G. niger. In 

 colour these specimens differ considerably (but in this we need not look for con- 

 stancy), the G. nigcr, from the general blackish or dusky hue of the body and 

 fins (these much darker than in its congener), well meriting its specific name ; 

 along the base it is of a dull yellow (in other specimens pale lilac-grey) ; the 

 general hue of the G. Britannicus is much lighter and more varied, the head, 

 body above, and a short way beneath the lateral line marbled with yellow and 

 brown, and points of black scattered along the lateral line ; yellowish on the 

 under parts."— TF. T., in Ann. Nat. Hist. vol. ii. (1839), p. 416. 



In addition to the points of resemblance noted in foot-note to my paper 

 in Annals, vol. ii., it may be mentioned that specimens received since it was 

 written, and exhibiting the character of each of the two species, in teeth, 

 present similar numerous lines of papilla on the head, so that the differ- 

 ence before noticed seems rather an individual than a specific character. 

 Both species are inhabitants of rocky shores. 



Dr. Pat. Browne includes " Gobius nnjer. Sea Gudgeon," in his list of 

 Irish Fishes, and Templeton notices it thus : — 



" Gohius nigcr, Linn., a mutilated specimen on the shore of Belfast 

 Lough, near Rockport." 



M. M'Calla informed me that black gobies are common at Galway, 



In the Ordnance collection (Dublin) are two specimens like Pennant's, 



compared (see Zool. Proc). The jaws may in both be called equal. Of four spe- 

 cimens of G. niger, one had a more depressed line from the head to the first dor- 

 sal, another a broad groove, and the remaining two displayed neither appearance. 



* See Cuv. and Val., t. xii. p. 12. 



t Cuv. and Val. thus describe the teeth : " Chaque machoire a une large 

 bande de dents en crochets, qui depassent les autres, et dont on compte 18 ou 20 

 a chaque machoire," t. xii. p. 10. The similarity in the teeth chiefly led me 

 to believe this species and mine to be identical. 



X Montagu remarks of the teeth, that " the under jaw is roughened by them 

 like a rasp." Mr. Yarrell describes the lower jaw " with fine carding-like teeth 

 in several rows" (vol. i. p. 353). Mr. Jenyns notes" fine card-like teeth in 

 several rows, the inner rows much smaller than tlie outer." — p. 385, 



