Royal Microscopical So&wti/. 107 



This species gives a very good illustration of the mode of 

 development of these bodies ; they could be traced from small 

 spherical particles of protoplasm, which could not be called cells 

 unless the absence of both investing membrane and nucleus be 

 excluded from the definition of that word ; these particles divide 

 into two unequal parts by a line across ; the smaller ]iart continues 

 to protrude until the whole looks like a round cell with a bud 

 attached to it; this bud gradually assuming a substance more com- 

 pact than the other part of the protoplasmic mass, becomes rounded 

 and more elongated ; the rays in the meanwhile bud out by degi'ees 

 from the larger section, the remainder of which forms the sarcodous 

 part of the mature zoosperms. These particles measure about 

 • 004 mm. in diameter, and correspond to the smaller cells * in 

 P. Bernhardtis. Other bodies occur which exactly resemble the 

 larger cells in that species. Between the two forms every gra- 

 dation in size is found, but I could not trace any other connection 

 between them. In the testis the larger cells occupy the outside 

 and extremities of the sacculi, the smaller particles fill the remaining 

 portion of the sacculi, and the mature zoosperms are diffused 

 through the centre of the testicular tube. This arrangement looks 

 as if the relation between the two forms was one of genesis ; be 

 that as it may, the zoosperms themselves do not begin to be 

 evolved except from the smaller particles. In Fig. 2 a is given a 

 representation of the larger cells from the testis of P. macidatus, 

 which exactly resemble both those of P. Bernhardus and those of 

 the present species. 



The spermatophora in this animal are attached in an irregular 

 manner and in close apposition to a broad elastic ribbon which 

 occupies the whole length of the vas deferens, so that it appears 

 that they all get into the female organs in one mass. In a front 

 view they are seen to be broadly lanceolate ; viewed on the side 

 they are lenticular. (Fig, 6.) They consist of a thick outer envelope, 

 which is attached by its base to the ribbon ; and an inner thin oval 

 structureless membrane, forming a closed sac which contains the 

 zoosperms; the length of the spermatophore, excluding the base, 

 is about " 034 mm., and the breadth is • 031 mm. 



The zoosperms of Galathiea squammifera (Fig . 7) somewhat 

 resemble those of P. j^lahjcheles, but are of a more elegant shape, and 

 differ also in the point of attachment of the rays. The caput is of 

 an elongated lanceolate form ; the representative of the tail is an 

 irregular mass of granular matter attached to the caput by a 

 narrow neck. The caput appears to be formed of a smooth, homo- 

 geneous, highly refracting substance, devoid of those internal mark- 

 ings which are apparent in the zoosperms of the Paguri and other 

 Crustacea. The rays are attached close to the neck of the granular 

 * Loc. cit., Plate XI.. Fig. 10. 



