144 THE ARMED BULL-HEAD FAMILY. 



The eggs are often deposited on the rocks at low water-mark in 

 straw-coloured masses. 



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 received a single specimen. 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." It is also mentioned that Kroyer 

 estimates the number of eggs at 3,000. So far as our observa- 

 tions 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 small masses of ova of this species, at 

 the beginning of October, considerably extends the spawning- 

 period. They are procured at low water near the pier-rocks at 

 St Andrews, attached to the roots of tangles and passing into 

 the interstices. The eggs measure from 1-7526 mm. ('0705 inch) 

 to 1"9050 mm. ('075 inch), showing that the ovarian examples, 

 mentioned in the Researches, as indeed had often been observed, 

 were nearly ripe. Each egg at this date (to take an instance 

 on 1st October) presented a large oil-globule and an advanced 

 embryo. The circulation was in active operation on the 

 27th November, the exterior of the egg being, further, coated 

 with many parasites. In January and Februar}' the water 

 containing the eggs was frozen, and remained so nearly a 

 month, yet, on the 2nd March, some of the embr3'os were alive, 

 and, though the water could not be changed, as the pumping 

 apparatus was under repair, were safely hatched. The re- 

 markable hardihood of such eggs is in contrast with pelagic 

 ova, which, as a rule, would have been killed. 



The egg-capsule (Plate I, fig, 7) is very tough, and rebounds 

 from the needle under pressure like a ball of india-rubber. 



' op. cit. 210, quoted Rept. S. F. B. 



