230 



Part III. — Thirteenth Annual Report 



and ventral ly. The pectoral fins have similar pigment — a feature 

 worthy of note. This larval fish was unusually active for a form with 

 its mouth as yet closed, its eyes devoid of pigment, and the yolk in 

 considerable bulk. It swam near the bottom of the vessel, resting at 

 intervals on its side. 



Next day (30th June) the hue of the pigment was distinctly yellowish 

 (lemon-yellow), though the whitish tint was still present along the upper 

 and lower borders of the muscle-plates. The finely ramified yellow and 

 black chromatophores not only occur on the body and yolk-sac, but also on 

 the marginal fin. The mouth is opening (PI. VIII., fig. 16), and in some 

 hours after the sketch was made a little pigment appeared in the eyes. 



]S"o similar form had previously been obtained in the tow nets, for the 

 majority of those with a yolk still bulky and the mouth closed have a 

 comparatively narrow translucent marginal fin of nearly uniform breadth, 

 without the marked caudal narrowing so characteristic of this form. It 

 belongs therefore to a stage apparently und escribed, unless it be an 

 abnormal example. In the larval flounder, the yellowish pigment-grains 

 are characteristic, and the body is slender and elongated ; in the dab, the 

 lemon-yellow pigment is grouped in two lines (dorsal and ventral), and this 

 is the form to which the present example most probably belongs. The 

 condition in the plaice, lemon dab, long-rough dab, and other common 

 pleurorectids offers no resemblance. It is true some of the topknots have 

 not been investigated, but in Muller's topknot the eggs have an oil-globule. 

 The larval fish from an unknown egg (G) mentioned in the ' Researches ' * 

 appears to approach it most closely, but it differs in the absence of the 

 pre-anal portion of the marginal fin, and in the fact that the mouth is 

 open on issuing from the egg, as in the plaice. Moreover, the pigment 

 is from the first brownish-yellow. 



4. On the Spawning Period of the Armed Bullhead and the 

 Vitality of its Eggs. 



Parnell gives May as the spawning period of this species. Couch says 

 nothing more than that the spawning period is stated to be spring ; while 

 Day describes a female, 5 inches long, from Southend, in February, as 

 having its comparatively large eggs nearly ripe. In the ' Researches ' f 

 it was stated that the females caught in the sprat-nets in the Tay showed 

 nearly ripe ovarian eggs on the 16th December, and that they had a dull 

 golden colour, while the structure of the zona (capsule) is given. The 

 males at the same time showed well-formed sperms. It is added that 

 the species seems to spawn from January (or perhaps December) to 

 April. In the recently published 'Scandinavian Fishes' the authors 

 observe | that " the males are so rare that neither Kroyer nor Ekstrbm 

 " has met with a full-grown example ; nor, during late years, has the 

 " Royal Museum met with a single example. It is probable that it is 

 " only during the spawning season that they live in so shallow water as to 

 " be in any danger from the nets used in shore fishing. The spawning 

 " season is in spring ; in March and April, or the beginning of May. We 

 " have no information as to the way in which the roe is deposited, or the 

 " development of the fry." So far as our observations go the males are 

 by no means rare, and they accompany the females into the shallow 

 water, and pass into the estuaries of the Eden and the Tay. The 

 remarks published on the subject have escaped the notice of the authors. 



The occurrence of a small mass of ova of this species, on 1st October, 



Trans. Royal Soc. Edin. t vol. xxxv. part iii., p. 835, and PI. xviii. fig. 1. 

 t Op. cit., p. 674. t p. 210. 



