306 THE SAND-EEL FAMILY. 



a spawning-pei'iod comprising 6 months of the year, or secondly 

 that it spawns every 6 months, viz., about June and about 

 December. Although one cannot be too careful in making 

 conjectures upon these points, yet we shall see that there are 

 facts with regard to the larval and post-larval forms which tend 

 to corroborate the latter hypothesis — that the lesser sand-eel 

 has two spawning-periods in a year. 



The female, which is larger than the male, appears to carry, 

 when ripe, about 10,000 to 30,000 ova. This, as we have 

 already observed, is not a great fecundity for a fish with 

 pelagic eggs, so that without further knowledge we might 

 surmise that the sand-eel has demersal eggs. The ripe female 

 bores its way rapidly through the loose sand below tide-mark, 

 and whilst doing so, discharges its eggs into the surrounding 

 medium. Couch remarks, ' It is in this retreat, concealed and 

 sheltered with the sand of the shore, that this launce sheds its 

 roe, the grains being scattered as it passes.' Each egg is 

 covered with a glutinous secretion, which causes it to adhere to 

 the surrounding sand, in which it is safely protected. Here 

 we have an explanation of the fact that the egg of the sand-eel 

 eluded capture in St Andrews Bay although diligently sought 

 for by surface-nets, bottom-nets and dredges. In fact the 

 details with regard to the eggs are derived, not from captured 

 specimens but from ripe ovarian eggs artificially extracted from 

 the female. 



The ovarian egg of the lesser sand-eel has at first no special 

 oil-globule, but by the time it is ripe a large and conspicuous 

 pale oil-globule is present (Plate III, fig. 15). 



When ripe in June and July the ovary (roe) is of a deep 

 reddish hue, and the majority of the eggs may be ripe at a 

 given time. The ripe egg appears to be of nearly the same 

 size as that of the larger sand-eel, but its oil-globule has a dull 

 golden or honey-colour (pinkish-orange by transmitted light), 

 and thus differs materially from the greenish oil-globule of the 

 larger sand-eel. Occasionally, as in other forms, a larger and 

 a smaller oil-globule are present. The micropyle agrees in 

 structure with that of the larger species, and the eggs in the 

 same manner adhere to the surface of glass. 



