452 Holt — On the Eggs and Larvce of Teleosteans. 



The eggs, which appear about three-quarters ripe, or less, are spherical, opaque, 

 and whitish. The diameter in the largest is from l'25-l-31mm. There is as 

 yet no appearance of a single oil-globule, though oleaginous matter is, as usual, 

 abundant in the egg contents. The zona, surrounded by the granulosa, is thick 

 and multi-laminate, with very conspicuous radial pores, terminating in minute 

 surface punctures. There is no trace of the mosaic of concave hexagonal facets 

 described and figured by Raffaele {op. cit., p. 65) in his species No. 4, attributed 

 to this family, nor does an optical section show the tubercles found by Costa on 

 the ovarian egg of M. coelorhgnchus. My specimens, however, had still a consider- 

 able period of intra- ovarian life before them. 



Pleuronectid^. 



Rhombus Isevis (Rondel). Tlie Brill or Britt. 



(PI. XLViii., figs. 13 and 14.) 



A female was obtained in Blacksod Bay on the 16th June, and proved to 

 contain ripe ova : I could not fertilize them, as no ripe male occurred on the same 

 occasion. 



The ripe unfertilized egg (fig. 13) floats buoyantly, and has a diameter varying 

 from 1*25 mm. to l"37mm., with a single pale oil-globule {o.g.) of "21 mm., which 

 in some cases shows a faint, dull-yellowish colouration round the edge. The yolk 

 is colourless, clear, and homogeneous. The punctures of the zona are very evident, 

 and the radial pores are very conspicuous in optical section ; the zona has the 

 appearance of being very much wrinkled, as is the case in some ova before fertili- 

 zation. Examination of flattened ova under a high power shows that whilst the 

 external surface is smooth, the zona is not of luiiform thickness throughout, the 

 internal surface being raised into ridges, similar to, but more pronounced and numer- 

 ous than, those in the unfertilized ova of Pleuronecfes cynoglossus. This may be due to 

 artificial causes. This observation may, I think, be taken as confirming RafPaele's 

 surmise {op. cit., p. 48) that certain pelagic ova (having a diameter of l'32mm., 

 with an oil-globule of "21 mm.), taken by him at Naples in the summer, belonged 

 to this species. The differences of measurement are insignificant. M'Intosh and 

 Prince {op. cit, p. 847) obtained similar ova at St. Andrews in February and 

 March, so that the spawning season of this form appears to extend over a consider- 

 able period in the British Isles.* 



* Dr. T. "VVemyss Fulton records a ripe female in May, from the mouth of the Forth — (" Spawning and 

 Spawning-places of Marine Food-fishes," Eighth Annual Report of the Fishery Board for Scotland, 1880, 

 pt. iii.). 



