102 RECORDS OF THE AI'SIKALIAN MI>EI;m. 



represented in his several specimens by six, eiglit or ten canals 

 lespectively. Gilclirist found tlie radial canals of C. capen^e to be 

 invariably six in number. 



ClrcJiliir caiitil. — The circular canal, which is a prominent feature in 

 vertical sections of the Medusa, is wide and lies directly above the nematocyst 

 ring. The eudoderm of the outer wall of the circular canal consists of 

 columnar cells the nuclei of wdiich lie close together near the cell margins, 

 which border upon the lumen of the canal. These columnar cells pass over 

 directly into the endodermal lining of the tentacle. 



The endoderm of the inner wall of the circular canal is formed of 

 small cells which contain {)igment-granules. These cells pass dii-ectly 

 into the endoderm cells of the ladial canals, which, however, are 

 unpigmented, and so come into relation with the endoderm of the stomach. 



The pigment-granules lodged in the cells of the inner wall of the 

 ciicular canal form a ring of pigment, the inner maigin of which is well 

 defined. Its outer margin is irregular and sends projections into the 

 columnar endoderm cells of the outer wall of the circular canal. These 

 projections lie in the intervals between tlie bases of the tentacles, and do 

 not extend into the endodermal lining of the tentacles, which aa a 

 consequence are unpigmented. 



Ootuids. — The sexes are sepai'ate. The gonads wei'e studied in both 

 male and female Medusae by means of serial sections cut in two directions, 

 vertically and transversely. The gonads are very well developed and are 

 lodged in the subumbrellar cavity. They occupy almost the whole of the 

 subumbrella, extending from the velum upwards alongside of the stomacli 

 and to a considerable extent above it. They do not, however, extend to 

 the apex of the body, but leave a small circular area above the stomach 

 quite devoid of gonads. 



The gonads form a ring around the stomach below the radial canals 

 and extend upwards into the subumbrellai' s[)ace where they aie separated 

 for a short distance by vertical partitions of ectoderm, above which they 

 unite once more to form a continuous ring around the stomach. There is 

 no brood-pouch above the stomach. 



The arrangement of the gonads in (J. hasirelll is thus associated with 

 the radial canals and their relation to the subumbrellar cavity. 'J'he 

 ludial canals are shoit and are given off from the stomach diverticula at a 

 very low level. Consequently there is a large subumbrellar space, lined 

 throughout hy ectoderm, between and abt)ve the radial canals. This ecto- 

 dermal lining of the subumbrellar cavity comes into contact above and 

 below the radial canals and so forms low vertical partitions com[)osed ki^ a 

 double layer of ectoderm and a middle one of mesogloea. 



The partitions below the radial canals extend downwards for a very 

 slunt distance. Those above the radial canals are developed to a greater 

 extent, but are not carried up to the apex of tlie subumbrella as in ('. 

 capense, where they form cotnplete septa between the gonads, so that the 

 ovaries or testes cotne to occupy si.x pouches or vertical divei'ticula of the 

 subumbrellar cavity. The arrangement of the gonads in ('. /nisircJII thus 

 differs considerably from that described by (jiilchrist in the Cape species. 



