IIG 



be exerted from behind forwards. To examine the eggs and keep them alive they must 

 be received when pressed from the fish into a bottle of clean sea water. By squeezing 

 a number of captured soles in this way in March, when the ovaries are found to be 

 much enlarged and soft to the touch, some are found from which transparent eggs can 

 be pressed out. When a considerable pressure is exerted part of the contents of the 

 ovary can be squeezed out of any sole in which the ovaries are large, but when the 

 ripe transparent ova have once been obtained it is easy to distinguish them from the 

 .smaller unripe ova w^hich escape when too much pressure is applied. These unripe ova 

 are yellowish-wliite and quite opaque : they do not separate from one another when 

 they fall into sea water, and membranes containing blood, derived from the tissues of 

 the ovary, are usually seen connected with them. In March a number of soles taken 

 at one haul of the trawl include, besides somewhat small immature specimens and males, 

 some large females which yield no ripe eggs, whose eggs have not yet reached maturity, 

 and only one or two from which ripe eggs can be obtained. Very often only a small 

 number of ripe eggs can be obtained when the fish is first squeezed, afterwards unripe 

 eggs escaping. This proves that the eggs in the ovary are not matured all at once, 

 but in gradual succession. But the process of ripening seems to become more rapid 

 towards the end of the spawning period in a given fish than at the beginning, and the 

 eggs are evidently extruded immediately after they are ripe ; for although I have 

 examined large numbers of female soles which yielded a few dozen ripe ova, and whose 

 ovaries al^er the extrusion of these remained distended with unripe ova, I have only 

 once found a specimen whose ovaries contained ripe ova only. Tliis specimen was 

 captured in a small-sized trawl worked from a Newlyn drift-net boat, on the morning 

 of March 23, 1889. I squeezed several thousand ripe ova from it, and the ovaries 

 were then completely empty. When uU the ova of one season are shed the ovaries 

 are left as flaccid sacs which soon shrink considerably in size. Fish in this condition are 

 usually said to be " spent " or " shotten": the latter is the Scottish expression. The 

 specimen just referred to was of very large size. It measured 20^ inches in length, 9i in 

 breadth. The boat by which it Was taken was trawling at a depth of about 30 fathoms 

 on the north-west side of Mount's Bay, off the coast of the Land's End pi-onioutory. 

 At the same haul, and in others previously made, shotten females, partially ripe and 

 unripe females were taken. The only conclusion to be drawn fi'om these facts is that 

 only a few ova are ripened at a time in a given female at the earlier stages of the 

 spawning process; while at the later stages though a large number of ova are ripened 

 at one time they are very soon shed, and therefore the capture of a female at the par- 

 ticular moment when she contains a large number of ripe ova is a rare occurrence. 



As stated above the spent condition of the female is easily recognised, ami when 

 only spent females are captured the end of the spawning period for the species is 

 determined. I investigated the duration of the period during the two successive 

 seasons of 1888 and 1889, and found that it ended some weeks earlier in the latter 

 year than in the former, a fact which can only be explained by the warmer weather 



