284 ROBERT PAYNE TUOELOW OX 



oo. t. — oi>.sopliaf,'i';il tiil)e, iir canal. s e. — sensory ciiilhiliuiii. 



OS. — oscnlnni. .sep. — .scptnni. 



ot. — rliiipalial cnncrclion (ntolitli). s f . — septal fiuini'l. 



p. — prnlxiscis. s g. — subgenital cavily. 



]) )). — pillar of llic jirobiLscLs. s ni. — septal muscle. 



r ('. — railial canal. s u. — .subunibrella. 



rli. — rliniialiiun. t. — tentacle. 



rli. I'. — rliopalial canal. v. — vesicle. 



ill. t. — rliopalial Iciilacle. za. — brownish green cells, .symbiotic algae. 



s. -ostein. 



PLATE 31. 



Fii;. 1. I'orlioii of Ihc calyx anil stem ol a si'ypliisl.niia ivilli a, liilly ilrvclo|icil Imil (h) attached. ^1, the oiillinc ,.| ih,. 

 same Iiiiil when contracted. 



l'"ig. 2. Similar to the preceding, except for the formation of a second buil (Ij') which bears the older one (6) upon its 

 ajicx. 



Fig. •'!. 'rill- form of llie ])laniila-Uke bu I daring the fir.-it tw i days after becoming free. A, B, aud C, are the successive 

 clianges in sliajie olisi-rvcd ill one specimen diiriuT; a few minutes. The arrows show the dii'ection in which it swims. 



Fiii. 4. Larva of prolialily the third day. A, lateral aspect; B. oral aspect. 



Fig. 5. A larva of alinui the same age, 48 hours or over. 



Fig. 6. Another larva of 48 hours or 0VCT-. 



Fig. 7. Larva of the fourth day. 



Fig. 8. Free scyphi.stoma of the fifth day, with radimeiits of four tentacles. The arrows show the direction of progres- 

 sion and rotation. 



F'ig. ft. A scypliistouia of ali ■ut the same age, with the ruilimeiits of eight tentacles. 



Fig. 111. "im1 aspect of a similar hirva, [icrhaps somewhat younger. 



Fig. 11. A scyphistoma a little iii ire advanced, probably in the fifth day. 



Fig. VI. A still more advanced .scyphistoma of the fifth day. The four lentacles Hrst formed are uiiieli longer than the 



other four. . 



Fig. 13. .Scyphistoma of the sixth day, attached, and with eight tentacles. 



Fig. 14. .Scypliistouia. with rudiments of the .second set of eight tentacles. Two tentacles of the first series are bifur- 

 cated. 



Fig. 15. Scyphistoma with sixteen tentacles fully developed, in the attitude of feeding. 



Fig. 10. Oral aspect of a similar specimen. 



FLATE ?,■>. 



Fig. 17. Scyphistoma sliovving first traces of rhopalial structure. 



Fig. 18. A small jiortion of the margin more highly magnified. 



Fig. 10. Scyphistoma at a .slightly older stage. 



Fig. 21). Small part of the margin of a similar larva. 



Fig. 21. .\ii early stage in strobilization. 



Fig. 22. A rliopalial tentacle of the same siiecimen seen from the side. 



Fig. 2.'J. An older rlii>iialial tentacle. 



Fig. 24. Sti-oliila in which the rhopalial tentacles h.ave begun to degenerate. 



