HALOPSIS OCELLATA. 



101 



adult. Specimens measuring an incli and a half in diameter have 

 as many as twelve chymiferous j,.^ ^^^ 



tubes, the cavity from which the 

 tubes originate being irregularly 

 shaped ; it is not till the Medusa 

 measures from two to two and a 

 half inches in diameter, that it 

 takes the regular star-shaped form 

 of Fig. 143 ; it is then also that the 

 genital organs first appear, like 

 threads on each side of the tubes. 

 Additional chymiferous tubes are 

 formed quite irregularly as diver- 

 ticula sent off from the digestive pouch, as in other ^quoridae. It is 

 quite a common thing in this species to have two actinostomes, in speci- 

 mens where the central cavity is very elongated and irregular in out- 

 line, a beginning, perhaps, of a transverse fission similar to that observed 

 by Kolhker in Stomobrachium, but which I have never noticed in our 

 species. In a still younger Medusa (Fig. 149), not measuring more than 

 a fifth of an mch in height, and which I suppose to be the young of this 

 species (it cannot be the young of Tm^ojisis diademata ; see the draw- 

 ings of the young of that species), we find already four eyes between 



Fig. 149. Fig. 160. 



two of the chymiferous tubes (Fig. 150), but having only two to three 

 granules in each, one large tentacle at the base of the chymiferous 

 tubes, one in the middle, and rudimentary tentacles of the third set in 

 the intermediate spaces ; on each side of these rudimentary tentacles 

 are long cirri ; there are no ovaries. It is interesting to see that among 

 the JEquoridas, the flattest of our Medusae, the young have a deep bell 

 (Fig. 149), which becomes gradually shallower, as in the other Campanu- 

 larians. The deep bell of the young Halopsis is totally different from 

 the other form of young .^Equorea figured hereafter, which resembles 



Fig. 146. Magnified part of circular tube, c, tentacular cirri ; e, compound eye ; t, main ten- 

 tacles. 



Fig. 147. Magnified view of one of the eyes, to show arrangement of granules. 



Fig. 148. Young Halopsis ocellata, natural size. 



Fig. 149. Young Halopsis ocellata, a fifth of an inch in height. 



Fig. 150. Magnified portion of circular tube of Fig. 149. c, c, c, c, cirri ; at base of each is 

 placed an eye. 



