STRUCTURH AND ])1;\"1':T,()PMI':NT ()]■" COl'.LOrLANA. 71 



in the external part and is expanded terminally into an ampulla-like 

 swelling. The invaginations often contain a sperm mass, so that it is 

 evident that they serve as sperm-receptacles. 



(12). The male gonad develops as some separate compact masses 

 of sperm-cells along the canals mentioned above. Each sperm-cell 

 mass or testis is provided with a duct that opens on the dorsal surface 

 of the body, and serves in leading the spermatozoa outside. 



(13). In the body parenchyme, muscle-fibres are developed much 

 better than in ordinary ctenophores; besides, there occurs a peculiar 

 element of unknown nature that resembles somewhat in appearance the 

 granular gland cell of the epidermis. Moreover, there is a system of 

 very delicate fibrous bodies which is probably the nervous system. 



(14). The newly laid egg shows a remarkable resemblance with 

 that of ordinary ctenophores, but for the much smaller quantity of the 

 gelatinous substance outside of the egg-body. It consists of an ectoplasm 

 presenting a granular appearance and an endoplasm with an alveolar 

 structure. The egg develops under the body of the mother animal 

 without becoming pelagic. 



(15). The segmentation of the egg was observed up to the 64-cell 

 stage; it advanced almost precisely as in the eggs of ordinary ctenophores. 



(16). The epibolic gastrulation is accomplished similarly as in the 

 eggs of ordinary ctenophores. In the gastrula persists an opening at 

 the animal or micromere pole for some time after the closure of another 

 opening at the opposite vegetative or macromere pole. 



(17). The gastrula develops into a typical cydippid-like embryo 

 which is furnished at one pole of the subspherical body with a round 

 mouth-opening and at the opposite pole with a sense-organ, besides a pair 

 of tentacular apparatuses and eight comb-plate rows situated laterally. 



(18). As development advances, the body of the embryo comes to 

 show a strong lateral com|)ression, growing much wider in the tentacular 

 direction; at the same time, the pharynx is divided into two portions, 

 of which the external portion becomes widened in the tentacular direction, 

 and the internal in the sagittal direction. 



(19). For some time after hatching, the larva swims about actively 

 in water by means of comb-plates, but gradually comes to remain at 

 the bottom, where it begins to crawl on the surface of the everted 

 external portion of the pharynx. 



(20). Finally, the larva gives up swimming, the cilia of comb- 

 plates falling off, and the basal sole of the larval body becomes widely 



