St. Andrews Marine Laboratory. 435 



or that are fixed to submerged stones and rocks. Amongst 

 others, however, the pelagic ova of the grey gurnard*, and, 

 as shown by Mr. G. Brook f, the rockling \ and the lesser 

 weever§ present oil-globules. It is well to remember also 

 that the abundance of oil does not in any degree cause the 

 ova of the cottus, fifteen-spined stickleback, or those of the 

 salmon or trout to float. A feature noticeable in most 

 pelagic eggs is the delicacy of the investing capsule {zona 

 radiata) and the crystalline translucency of the yolk-mass. 

 Another is the fact that the embryos produced by such eggs 

 are generally in a rudimentary condition, some, such as the 

 young of the common flounder (Pleuronectes Jiesus), cod, 

 haddock, whiting, and others, being devoid of mouth and anus 

 as well as of blood-vessels. The minuteness and delicacy of the 

 young Gadoids and Pleuronectidge, and the difficulty of rear- 

 ing them in confinement after the absorption of the yolk-sac, 

 are considerable obstacles to the successful extension of such 

 forms by artificial means in exhausted water. 



In connexion with these pelagic ova the changes which 

 ensue when ova captured and kept in the water of the open 

 sea are placed in littoral water, especially that near a harbour 

 or estuary, have not yet been fully investigated. They are 

 not more remarkable, however, than those which occur in 

 certain adult invertebrates when similarly treated. 



The Young of the Ling (Molva vulgaris, Flem.). 



In the Trawling Report allusion was made || to the imma- 

 ture examples of the ling that had come under observation, 

 and which for the most part had been procured by the hooks 

 of the liners. Mr. Day states^! with regard to the young, that 

 " the back and sides are yellowish olive, broken up and 

 divided into patterns by pale lilac lines." The striped con- 

 dition of the young ling affords such a contrast to the boldly 

 spotted state of the young cod that it is desirable to record it 

 in greater detail. About the middle of December a specimen 

 3-i- inches long was found in a pool at the commencement of the 

 East Rocks. In this an olive-brown band passes from the 

 tip of the snout in a line with the middle of the eye straight 

 backward to the base of the caudal fin-rays. The pale 

 ventral surface bounds it inferiorly, while dorsally a stripe 

 having a beautiful opaline lustre runs from the tip of the snout 

 over the upper part of each eye to the base of the caudal 



* Report of the Royal Commis.sion on Trawling, 18S5 ; p. 633. 

 f Journ. Linn. Soc. xviii. pp. 273 and 299. 

 \ Ibid. p. 298. § Ibid. p. 275. 



|| Op. cit. p. 360. % Op. cit. p. .'306. 



