433 Miscellaneous. 



thickness and formed of a tenacious, dense mucus, which refracts 

 light and gives it a yellowish tint posteriorly, where it is thickest. 



As soon as the twin spermatophore comes in contact with the 

 water, a white pearly substance escapes from it continuously in the 

 form of a filament, and becomes gradually disaggregated in the liquid. 

 By a high magnifying power this is seen to consist of spermatozoids, 

 with a certain number of fine molecular granules, which abound 

 especially in the last portions of the matter. 



In Nephelis a spermatophore of the same kind may be detected in 

 each of the sacs terminating the male organs. They are white, ovoid, 

 and a little flattened ; their length is about 1 millim., and their 

 breadth about l millim. Each of these is independent of the other, 

 and closed at all points. Their contents are analogous to those of 

 the same bodies in the Glossiphonice, but their envelope is colourless, 

 and much softer and more delicate. 



These spermatophora are found superposed, to the number of two 

 or four, close to the bottom of the slender portion of each of the 

 ovarian tubes. They are similar to what they were in the sacs of 

 the male organ, but their volume has become a little greater and 

 their envelope a little thicker. Besides these, in the dilated ascending 

 portion of the same female organs, there exist two or four other 

 analogous, but vermiform, bodies, 2 or 3 millim. in length, a little 

 inflated in the middle, narrowed to the two extremities. These 

 owe their volume to the ova developed within them. These bodies 

 have a colourless envelope, striated longitudinally, scarcely granu- 

 lated, thicker and more resistant than that of the preceding ones, 

 from which they are distinguished by the ovules in course of evolu- 

 tion which they contain in the midst of the spermatozoids. They 

 thus constitute true ovo-spermatophora. The ovules are more nu- 

 merous and more advanced in their evolution in proportion as the 

 spermatophora in which they are seated are nearer to the genital 

 orifice. 



The ovules complete the whole of their evolution up to the period 

 of fecundation within the ovo-spermatophora, and in immediate con- 

 tact with the fecundating corpuscles. In each spermatophore they 

 are seen in every stage of growth. The most developed ones are 

 always seen in the middle and largest part of the bodies, from which 

 they escape as they are fecundated. They escape by dehiscence, in 

 consequence of a gradual thinning of the envelope during the forma- 

 tion of the corneous protective capsules. They are then found free 

 in the oviducts to the number of from four to twelve on each side ; 

 between the vitelline membrane and the vitellus they have a consi- 

 derable number of spermatozoids, which are generally already mo- 

 tionless. If mature ovules be taken in the ovo-spermatophora, tlie 

 penetration of the spermatozoid into the ovule through certain points 

 of the vitelline membrane may be traced ; the spermatozoids are seen 

 moving for an hour or two round the vitellus before the extrusion of 

 the eggs ; then some of them become liquefied and unite with the 

 substance of the vitellus. — Comptes Rendus, August 12, 18G1, 

 p. 280. 



