322 HABMOTHOE IMBRICATA. 



about an eighth the size of the larger, — the latter, however, being nearly equal, and their 

 nuclei contain several nucleoli. 



Some females retain a considerable number of ova till the middle of May, though 

 the body is by no means distended. Many have been discharged. 



Fig, 27. 



Developing ova of Harmothoe imhricata. x 280. November. 



Besides the larger ova are many minute forms attached to the germinal tissue, so 

 that the spawning period is prolonged, or the minute ova retained or absorbed. 



About the middle of February specimens with masses of ova under the scales are 

 common. The slightly pinkish eggs are attached to each other and the surface by a 

 transparent mucous secretion, so that they do not readily fall off. They form a dense 

 layer under the scales, and in some are almost invisible. The process would appear to 

 be protective, giving them the shelter of the adult, and enabling them to escape the 

 attacks of predatory crustaceans or other forms. They have a diameter of about *56 

 to '78 mm. ; the zona is delicate and translucent, yet resists some pressure. In the 

 perivitelline space are a few granular cells, such as those found in various eggs of fishes 

 (e.g. the gurnard). In structure the yolk is minutely granular, the figure showing the 



Fig-. 28. 



Segmenting ovum of Harmothoe imhricata. 



egg cleft into two spheres (Fig. 28). The eggs are so opaque that section alone reveals 

 the structure. In confinement the females carrying ova readily throw off their scales a 

 feature probably due to the absence of nourishment and the condition of the water. 



The males have their spermatozoa fully developed at the end of January and 

 beginning of February. These consist of simple tapering rods with a very attenuate 

 filament from the broader end (Plate XXVI a, fig. 1). They thus differ in shape from 



