234 



Part III. — Thirteenth Annual Report 



but it offers certain points of difference with our examples, which were only 

 a little less. Thus permanent fin-rays occur in the second dorsal, and the 

 number of embryonic rays in the tail is much less. The snout is more 

 produced, the notochord slightly bent up, and an air-sac is present. The 

 black pigment, moreover, is much more general, and there are four reddish- 

 brown bands. Certain of these features are in agreement with, the post- 

 larval form above described, yet others, such as the arrangement of the 

 pigment on the head, the more extensive development of embryonic rays 

 on the tail, and the absence of an air-bladder diverge. Some of these, it is 

 true, may be modified by growth, and there are not many species of 

 gobioids with which to confound the example. It is much too large for 

 a similar stage of Gobius minutus and G. Jfavescens, while G. niger has 

 never been procured at St Andrews, though it has been found in the 

 Forth. Its size would appear to correspond more with this than the two 

 previous species, though it approaches in this respect also the female 

 Crystallogobius nilssonii, yet it is somewhat larger than that form at the 

 same stage. But it has to be remembered that the season at which this 

 post-larval form appears is quite different from that in which such gobioid 

 forms are found, viz., in June and July. 



7. On a Peculiarly Coloured Plaice. 



A plaice — measuring 10 inches in length and 5| inches at its broadest 

 part — caught by hook in St Andrews Bay on the 20th April, presented 

 the following pecularities in colour. The right side (coloured) was dotted 

 all over with black specks and touches, viz., a broad belt of these from 

 the head to the base of the tail in the median Hue ; then, after a paler belt 

 on the tail, the specks continue to the tip. The dorsal and anal fins were 

 much speckled, even to the tips, and a few specks occurred here and there 

 in the pale regions on the sides of the median broad belt. Small red 

 touches (less than usual), are uniformly scattered over the right side. 

 The white (left) side was speckled throughout with black, the granular 

 pigment being grouped in little masses, forming here and there larger 

 rosettes. The black specks invaded the fins — caudal, dorsal, and anal ; 

 while the white pigment was likewise curiously mottled. 



DESCRIPTION OF PLATES.* 

 PLATE VI. 



Fig. 1. Egg of long-rough dab immediately after its escape from the ovary, and 



before impregnation, 21st March 1895. x about 31. 

 Fig. 2. The same egg, next morning (22nd March), showing the enlarged perivitelline 



space, x about 18. 



Fig. 3. Fertilized egg of the same species (fertilized at 6.20 p.m. on the 21st) at 



12.20 p.m. on the 22nd March, x about 18. 

 Fig. 4. A similar egg at the same hour, showing minute oil-globules scattered over 



the yolk. A portion of the capsule (zona) is indicated at z. x 52. 

 Fig. 6. An egg one day older, showing the early blastoderm. The groups of minute 



oil-globules are still numerous, x 52. 



* I am much indebted to Mr A. T. Masterman and Mr H. C. Williamson for 

 their kind aid with the figures indicated. 



