156 THE WEEVER FAMILY. 



The Weever Family. Trachinidae. 



The Lesser Weever. {Trachinus vipera, Cuv. and Val.) 



For the first account of the pelagic eggs of this species we 

 are indebted to the late Mr George Brook, who, with rare 

 enthusiasm, fitted up tanks of sea-water near his home at 

 Huddersfield, and studied the life-history of this form^ and 

 that of the rockling. He found that his captive weevers 

 in June deposited their eggs during the night, just as was 

 subsequently found in the spawning-pond at Dunbar in the 

 case of the plaice. They are buoyant eggs having a diameter 

 of 1'25 to 1'37 mm., and containing from 11 to 30 small oil- 

 globules (Raffaele says 4 — 10). They were subsequently got in 

 considerable abundance by Mr Holt, in Blacksod Bay and other 

 parts off Ireland, in June and July, and are common in St 

 Andrews Bay, at the surface, from May till July. The yolk 

 is clear and transparent and the oil-globules have a greenish- 

 yellow hue (Plate I, fig. 14-). The egg-capsule was thought by 

 Mr Brook to consist of two layers, and in section Mr Holt ob- 

 served that the outer region only took the yellow stain ; while 

 the inner was faintly affected by carmine. Practically, howevei', 

 the egg-capsule agrees with that of other pelagic eggs in 

 structure, as also does the micropjlar opening. 



Mr Brook gives a minute account of the early stages of 

 development of the Ggg as they were seen in April, and the 

 late stages as they occurred in July. They hatched in from 

 9 to 11 days. Dr Raffaele's examples hatched in 8 days in 

 spring, the eggs lying on the bottom during the last three or 

 four days. The spawning-period would seem to range from 

 April to July. Mr Holt found pale yellow pigment, in minute 

 round specks, in the developing embryo, before the appearance 

 of the free tail-region. As development proceeds, the yellow 

 chromatophores become stellate and have a brilliant orange 

 hue. They extend along the upper and lower margins of the 

 tail, and along the gut on either side. Small black chromato- 

 phores have also appeared : others by and by occur over the 



1 Journ. Linn. Soc. vol. 18, p. 274. Pis. 3—5, 1884. 



