NOTES AND MEMORANDA. 399 



in the observations of other years, but these were much less numer- 

 ous, and the omission does not prove that Muggisea did not occur 

 in those years. Peach's collections were made in Fowey Harbour 

 and just outside of it. — J. T. C. 



Hippoglossus vulgaris, Linn, (the Halibut). — On the 30th April I suc- 

 ceeded in pressing some apparently ripe ova from a female halibut in 

 the market. I had no opportunity of examining the ovary, but 

 external pressure caused the extrusion through the genital orifice of 

 a quantity of yellowish viscous putrid liquor, amongst which were a 

 quantity of collapsed zonae radiatse, and the ripe ova referred to. 

 The fish was dead, and appeared very stale. All the ova were dead 

 and more or less decomposed, but some were sufficiently fresh to 

 illustrate the living condition. 



The diameter varies from 3*070 to 3"818 in my specimens ; the 

 yolk conforms to the condition met with in other dextral Pleuronec- 

 tids, being colourless, translucent, and homogeneous, and destitute 

 of an oil-globule. The zona is thin, measuring "03 to '04 mm. in 

 optical section, and remarkably delicate and flexible. 



Externally it is finely dotted ; internally are a number of slight 

 ridges, which give the whole structure the appearance of being 

 irregularly scribbled with fine striae. Laminse are clearly visible, 

 but radial pores cannot be seen in optical section in fresh prepa- 

 rations. 



The ova are evidently pelagic, and the extreme delicacy and flexi- 

 bility of the zona (which is such as to render it difficult to pick up 

 an egg with the forceps without causing it to collapse) suggests that 

 a large perivitelline space may be formed under natural conditions, 

 since this takes place in the long rough dab {Hippoglossoides 

 limandoides) , which is the nearest relative of the form before us, 

 and in which the conditions of the zona are very similar. 



Ripe but unfertilized ova were obtained by Prof. Mcintosh 

 shortly afterwards, and from a brief note which he has published 

 (Ann. Mag. Nat. Hist., July, 1892) it appears that some of them 

 were a little larger than the largest of mine. 



It is evident that the halibut's ova are not commonly to be met 

 with along our coasts, since such relatively enormous structures could 

 not fail to have attracted attention in the tow-nets. — E. W. L. H. 



Rhombus maximus, Linn, (the Turbot). — I am not aware that the 

 ova of this important species have ever been described in sufficient 

 detail to ensure their recognition if met with in the contents of the 

 tow-net, nor is there any description whatever of the embryonic 

 and larval stages. 



NEW SERIES. VOL. 11. NO. IV. 30 



