BUDS OF CBPHALODISCUS NIGRBSCENS. ' 47 



the alimeutary system (tig. 37, plate 5). A large testis extends as far as the extreme 

 posterior end of the visceral mass, and may occasionally send off a lateral branch 

 which is lodged in the stolon. The duct at the anterior, pointed end of the testis 

 differs from the corresponding duct of the ovary in having no red pigment, or at 

 most a few specks of red. 



A transverse section of the testis shows a moderately thick wall of unifonn 

 character throughout (except in the foremost portion or duct), composed of four or 

 five layers of cells in various stages of spermatogenesis. The central cavity is 

 occupied by large masses of spermatozoa. 



The openings of the ducts of both ovaries and testes lie at the bottom of shallow 

 depressions, the epithelium of which is composed of taller and more closely set cells 

 than those investing the greater part of the body. 



Buds and Budding. 



A bud in its earliest stages of development appears as a small clavate mass 

 (fig. 60, plate 7), the free end of which gradually flattens out (fig. 61), and becomes 

 differentiated from the " body." The flattened terminal portion is of semicircular 

 outline, and develops into the anterior part of the buccal shield. The red line of 

 the buccal shield appears at about this stage, before the posterior edge of the shield 

 is clearly outlined. The shield becomes broader and more sharply defined from 

 the " ])ody " (fig. 62), and grows at a much faster rate than the latter (figs. 63-65). 



Fig. 65 gives a side view of a bud of the same age as that represented in fig. 64, 

 and serves to show the great mobility of the shield even at this early period of 

 development. The posterior flap of the shield can l)e Itrought sharply forward, 

 i.e. ventrally, and the " body " appears as an elongated pyriform structure projecting 

 from the middle oi the dorsal surface of the shield, and is continued back into the 

 tapering stalk. 



Shortly after this stage is reached the plumes begin to develop, as small hemi- 

 spherical projections situated dorsally to the middle of the shield, and arranged in 

 a curved line that runs immediately anterior to the " body " (fig. 66). The plume- 

 axes elongate and flatten into thick ovate discs, and the pinnules grow out from 

 the edges. 



After this, the shield increases at a relatively slower rate, the body enlarges 

 rapidly (fig. 67), and, in the later stages, the visceral mass begins to bulge 

 posteriorly (fig. 68), so that the stalk is no longer terminal, but on the ventral 

 side of the body. The plumes by this time have increased to the number of 

 twelve or fourteen, and the line of their bases has gradually changed from a 

 semicircle to almost a circle. 



As in C. dodecalophus, the shield of a young bud (with two pairs of plume- 





