CUBING HIS SOJOURN IN THE WESTERN PACIFIC. 



555 





9 gen pore. 

 ■■3 gen pore. 



Fig. D. Diagram of the uterus and male reproductive organs of 

 Coelodehi kiwaria. 



J and (f gen. pore, male and female genital apertures, glds. 

 round vagina, I. v. lateral water-vascular vessel, tes. testis, ut. uterus, 

 V. valve in l.v., ves.sem. vesicula semiualis. 



arrangement of the generative organs with the compact female glands and the testes 

 scattered on the dorsal side of each proglottis is also unlike what occurs in the above- 

 mentioned forms. 



In some respects the an-angement of the genitalia recalls that which obtains in 



the genus Muniezia but the 

 uterus is single. The first trace 

 of the reproductive organs ap- 

 pears in the younger segments 

 shortly behind the head, the 

 first structure to appear and 

 the la.st to disappear when the 

 proglottides are full of ova is 

 the cirrhus and its base. The 

 cirrhus bulb is large, when the 

 cirrhus is protruded it leaves 

 the proglottis about the junction 

 of the anterior two-thirds with 

 the posterior third. Close to it 

 opens the vagina. The vas de- 

 ferens leaves the cirrhus bulb 

 coils slightly and enlarges into 

 a large vesicula seminalis, which 

 even in the proglottides of the posterior end contains bundles of spermatozoa. The vas 

 deferens is then continued on and branches into a number of secondary ducts which end 

 in the dorsally arranged testes. There is no sign that the testes are double but probably 

 they are so. That is, probably no single testis lobe opens into a vas deferens which 

 runs both right and left. Each lobe probably opens on to either the right or the 

 left side of the animal. With the exception of the uterus the female organs are 

 also paired, and open on each side of each proglottis. The ovary and shell-gland and 

 vitellaria seem to be all aggregated near one edge of the animal, though the 

 histological state of preservation of the material did not allow this point to appear 

 with absolute certainty. The uterus is not paired. The first sign of it is a transverse 

 band of deeply staining cells which becomes differentiated right across the segment in 

 the centre of the body but nearer the anterior than the postei'ior limit of each 

 proglottis. A few segments behind that in which this transverse differentiation occurs 

 it is seen that further differentiations arise at right angles to the first and continuous 

 with it. Thus in this stage the uterus is solid and resembles the head of a rake, 

 with all the teeth pointing posteriorly. A little later a lumen arises within these 

 strands which is at first lined by a well marked epithelium. As the proglottis ages 

 the number of diverticula increase and their lumen swells, the intervening parenchyma 

 being at the same time absorbed. Thus it comes about that at first a lobed uterus 

 arises and then by the disappearance of the dissepiments the uterus becomes one 

 single undivided, smooth walled receptacle full of eggs. The ova are spherical with 

 one or two deeply staining yolk granules and an egg-shell which stands off from 

 w. V. 74 



