46 THE MEDUSAE. 



vertical position. The terminal otocyst is large, but the ventral bulbus is only 

 slightly developed. Just proximal to the sense organ is a deep exumbral pit 

 (PI. 13, figs, i, 5, p.) as in many discophores, perhaps sensory in function. 



The gonads, which, fortunately, are in very good condition, are by far 

 the most interesting feature of the specimen. They are not located in 

 genital pouches, but form a practically continuous band surrounding the 

 basal portion of the stomach proper. Close examination shows that this 

 band is not truly continuous, but is broken by eighteen or nineteen thick- 

 ened vertical ridges of the gastric wall (PI. 13, figs, i, 3). The gonads 

 themselves consist of a series of outpocketings of the gastric wall projecting 

 out into the subumbrella cavity, their cavities (PI. 13, fig. 3, g o.) opening 

 freely into the basal part of the stomach (PI. 13, figs. 2, 3). The very numer- 

 ous gastric cirri are arranged in a single continuous series, arising from the 

 wall just distal to the genital folds (PI. 13, figs. 1-3). The gonads are 

 mostly emptied of their contents. 



The smaller specimen includes about half of the central portion of the 

 disc, the entire margin and distal mouth parts being destroyed. There are 

 twenty-one canals in the fragment, therefore the total number was probably 

 about forty, as in the larger specimen. In the present specimen, however, 

 they are much narrower, and the intercanal spaces much broader, than in 

 the latter. The gonads present the same appearance, but, on the fragment, 

 there are four pillars subdividing the gonads, so that probably there were 

 only about eight in the complete medusa, instead of eighteen or nineteen as 

 in the larger specimen. 



In the larger specimen the subumbrellar surface is reddish brown ; the 

 gonads very pale brownish. In the smaller the entire fragment is of a deep 

 reddish-brown tint. 



The remarkable structure of the gonads outlined above may be easily 

 derived as the result of an advanced stage in growth from the more primi- 

 tive condition described by Vanhoffen for his much smaller specimen. 

 He has described and figured (: 02% p. 41, taf. 4, figs. 15, 16) seven (eight ?) 

 gonads, each consisting of three or four outpocketings of the gastric wall, 

 lying, not in gastric pouches, but directly at the base of the gastric cavity, 

 exactly as in the present specimens. To attain the condition exhibited by 

 the smaller " Albatross " specimen, we need only suppose that with growth 

 the gonads increase in width by the formation, on either side, of new sexual 

 folds, until the adjacent gonads practically unite. The spaces between them 



