MEM. M. C. Z., IX. No. 3. — ACALEPHS, POLYPS. 



19 



PLATE V. 



Development of the Trachtmedus/E, contimied. Yornig Stages of the Medusce of the Htdroida, 

 and AcRASPEDA. Figures from Alexander Agassiz, George J. Allman, J. Walter 

 Fewkes, Ernst Haeckel, and Fritz Mulleb. 



r. tb'. Kailial tube which has not yet grown 



to the circular canal. 

 ta. Tentacle. 

 tb. 

 tb'. 



'■ Ichymi 



ferous tubes. 



1-2. G!ossocodon eurybia {Liriope cnrybia). From Haeckel, Beitriige zur Natnrgeschichte der Hydromedusen, 

 Erstes Heft. Die Familie der llusselquallen (Geryonida), PI. IIL, figs. 29, 30. 



1. Young larva, with bell fully formed, seen from the oval side. The beginnings of four tentacles, which later 



form the embryonic tentacles, are seen as four small buds. vd. Velum. 



2. Larva of about the same age, seen from one side. ahr. Umbrella. 



3. From Fritz Miiller, Archiv fur NalurgeschicUe. 1859. PI. XL, fig. 16. 



3. Still older medusa, seen from one side. The provisional tentacles are considerably developed, and from their 



tips project the tongue-like spurs, cav. Cavity of the bell. ubr. Umbrella. 



4-". Glossocodon tcnnirnstris, sp. Ag. From Fewkes, Notes on Acalephs from the Tortugas, with a Description of 

 New Genera and Species. Bull. Mus. Cunip. Zool. Vol. IX., No. 7, PI. VII., figs. 2-5. 



4. Larval medusa \vith stiff embryonic (transitory) tentacles (em. ta.), in which the permanent tentacles are not 



developed. man. Manubrium (rudimentary in character), r. tb. Radial chymiferous tube. The club- 

 shaped bodies are, comparatively speaking, very large. 



5. Older larva, in which the embryonic tentacles {c7ii. ta.) have somewhat diminished in size, and a true tentacle 



(te. ) has begun to form. 



6. Older larva, where the tentacles [ta.) have grown much longer. The manubrium (man.) has also increased 



very greatly in size. Embryonic tentacle [em. ta.) reduced in size; almost lost. 



7. Older larva, wholly destitute of embryonic tentacles, while the true permanent tentacles (ta.) are very long, 



as in adult. 7nan. Manubrium, r. tb. Radial tube. ubr. Umbrella. 



