46 W. G. RIDEWOOD. 



unaltered by alcohol, formalin, and glycerine. The ovary may be described as a sac, 

 to one side of the interior of which are attached the ova (figs. 38-40, plate 5). The side 

 in question is that farthest from the median plane of the body. The smallest ovicels 

 are those at the oviducal or anterior end of the ovary, and the size of the cells 

 gradually increases as one passes towards the broad end. The larger ovicels are more 

 or less comma-shaped (fig. 40), which suggests that the proliferation of the germinal 

 cells takes place near the oviduct and on the side of the ovary farthest from the 

 median plane of the body, and that the production of the new cells causes a backward 

 distortion of the cells proliferated at an earlier period, so that these latter have each 

 a kind of tail directed towards the anterior end of the outer wall of the sac. The 

 hindermost member of the series is in some ovaries vastly larger than its neighbours, 

 and has become rounded off (fig. 38). It is heavily charged with yolk. 



The large ripe ovum, free in the ovarian sac, presumably escapes by passing 

 forwards between the mesial wall of the sac on the one side and the layer of ovicels 

 on the other, and, by causing a great distension of the red oviduct, passes out to the 

 exterior. There is in the present species no evidence to support the suggestion of 

 Masterman in the case of C. dodecalo^jhu.s (24, p. 512) that the oviduct serves merely 

 for the admission of the spermatozoa, and that the ova do not escape by way of this 

 duct, but are set free only by the death and disintegration of the body of the parent. 

 Indeed, the occurrence of an ovum in some specimens lying entangled among the 

 bases of the plumes immediately over the oviducts points to the normal extrusion of 

 ova throuo'h these ducts. 



At the posterior end of some ovaries occurs a kind of collapsed and irregular tube 

 (fig. 39), which looks as though it were an oviduct ; and the supposition is 

 strengthened by the ripest ova being found towards this extremity of the ovary. 

 But examination of sections shows that the tube in question ends blindly. Moreover, 

 the ducts of the testicular sacs of the male occur in positions corresponding exactly 

 with those of the red ends of the ovaries of the female, and the lumen of the male 

 duct is invariably clear, and bounded by well-defined epithehum. The tube at the 

 posterior end of the ovary is in all probability the hinder portion of the ovarian 

 sac which has collapsed after the discharge of a ripe ovum, and has not yet been 

 filled out by its successor. A similar twisted tulie is present in C. dodecalophus. 



Liberated ova are found singly among the buds in the blind ends of inhabited 

 tubes of the colony. They are yellowish white in colour, • 7 mm. in length and • 6 mm. 

 across. No segmenting ova have been met with.* 



The testis, when small, has the form of a pear-shaped sac, and bears a general 

 external resemblance to an ovary ; but when fully formed it is much larger than an 

 ovary, and is cylindrical in shape, frequently distorted, however, by pressure of parts of 



* Since the above was written, sections have been cut of some eggs of C. nigrescens which prove to be in a 

 state of segmentation. The only stage met with up to the date of this footnote is one in which a single layer of 

 tall, narrow cells surrounds an undivided mass of yolk. July 22, 1906. 



