100 Prof. M'Intosb's Notes from the 



tapered. The filiform tail is so attenuate that it is difficult 

 to distinguish it. 



As indicated, the ova varied in different examples. The 

 larger developing (not ripe) ova in some were all about the 

 same stage of advancement, though small ova occurred here 

 and there throughout. The capsule {zona radiata) is tough, 

 and contains, in the eggs approaching maturity, besides the 

 nucleus, the minutely granular yolk, which has a series of 

 small, deep greenish-yellow oil-globules distributed amongst 

 it. In ovaries somewhat further advanced, the ripe ova had 

 an average diameter of "7620 millim., and instead of the 

 numerous scattered globules all had now coalesced into a 

 single conspicuous oil-globule of a greenish-yellow hue 

 measuring '1950 millim. in diameter. The capsule is thick, 

 and may be divided into an external and an internal lamina. 

 The outer surface is minutely areolated or papillose, the 

 papillae being evident as a distinct border at a fold of the 

 zona, e.g. after rupture. In some the minutely complex 

 folds resemble those of a microscopic Meandrina. The 

 nature of this outer layer is still sub judice. It may be 

 either a follicular growth or more probably the result of a 

 special secretion for adhesion, though the latter at first sight 

 would hardly be supposed to be so regular. It can easily be 

 abraded from prominent folds of the Q^g, leaving the smooth 

 and glistening zona beneath. The latter is a hyaline and 

 minutely perforate layer, which assumes different appearances 

 under examination, such as rows of dots or finely crossed 

 lines. The micropyle is conspicuous in the form of a deep 

 pit, from which radiate a series of long furrows. 



When these eggs are removed from the ovaries and placed 

 in sea-water they adhere to the bottom of the vessel, so that 

 it may be inverted without detaching them. They are not, 

 however, firmly fixed, since they can be loosened from the 

 glass with a camel's-hair pencil or the point of a pipette. 

 They adhere in the same manner to the forceps or a slide. 

 In water they do not often adhere to each other, but do so 

 slightly when placed in contact. 



At the same period the majority of the most advanced 

 examples of the lesser sand-eel [A. tohiarms) at St. Andrews 

 present considerably smaller ova than the foregoing ; indeed, 

 throughout June and July only a single female here and there 

 is found in a ripe condition, yet perhaps hundreds are cap- 

 tured in a single sweep of the seine-net. These, however, 

 are, as a rule, smaller forms than those captured by the same 

 kind of net in the Forth, at Elie, where the ripe females are 

 considerably more numerous. On tlie other hand, ripe males 



