20 NORTH SEA INVESTIGATIONS. 



The spent female was 13| in. long, the ovary 3 yV and 4 xV in- fro™ 

 the ends of the ventral fin. Under the microscope it showed no yolked 

 eggs or opaque masses — apparently they had already been absorbed — 

 although the ovary had not lost its collapsed flaccid condition. Nearly 

 all the other females, although otherwise not indicating the spent 

 condition, showed more or less of the opaque granular masses in the 

 substance of the ovary, and I have little doubt that all had spawned. 

 The males also, I have no doubt, had spawned, the testes being some- 

 what larger and softer than in the immature. 



These fish had been feeding, but were not so crammed as those from 

 the Sylt grounds. In 10 the stomach was nearly empty, and the con- 

 tents of the intestine much digested, though usually containing a few 

 shells. Of the other 9 Lamellibranch remains were present in all, and 

 consisted chielly of Solen. One 13^ in. long had the stomach crammed 

 with bits of white molluscs' flesh about h in. long. These were the 

 ends of the siphon tubes of some Lamellibranch, apparently not Solen. 

 Polychaete worms occurred in 4. 



On April 2nd I examined a few small plaice caught by the shrimp 

 shove-net at Cleethorpes. Among them was a female 7^ in. long, the 

 end of the right ovary 1^, 2^ in., from the anterior and posterior ends of 

 the ventral fin respectively, the eggs under the microscope without 

 yolk and without any trace of granular masses. Another female was 

 7 in. long, likewise without any trace of granular masses. These fish 

 were undoubtedly immature. I have found it quite impossible to rely 

 with confidence on the relative length of the ovary, as a criterion 

 to distinguish between the immature and the spent condition. jMr. 

 Holt, in his discussion of the question (vol. ii. p. 368), states that the 

 length of the posterior process of the ovary in the immature condition 

 does not exceed one-third of the distance between the first ha?mal 

 spine and the caudal peduncle. This distance appears to be the same 

 as that which I have used as the standard, namely, from the anterior to 

 the posterior end of the ventral fin, but I am in doubt about the point 

 from which the length of the posterior process was measured by 

 I\Ir. Holt. To obtain a constant point of measurement, I have 

 measured the length of the ovary ia situ, from the front of the first 

 ray of the ventral lin to the posterior extremity of the ovary. In 

 the immature fish the length of the ovarv thus measured is less 

 than the distance from the end of the ovary to the posterior end 

 of the ventral fin, but more than a half of that distance. It is 

 usually very little less than |rds. Now in specimens in which the 

 granular masses are conspicuous, the ovary is often less than |rds 

 of the described distance. I have never seen these granular masses 

 in a plaice less than 9 in. long, so that there is no reason at present 



