246 ZOOPHYTES. 



Plate L. Fig. 3. The same original hydra 308 days after dissolution of the roll. 



4. The same, in 322 days. Both in this and in the preceding 



figure, the progeny omitted. 



5. Original hydra and its descendants, as appearing 371 days after 



liberation of the Medusae. 



6. The same, as in a year and nine months. 



7. A separate view of the parent, a, and one of the young, then 



nearly of its own dimensions. 



8. The original hydra, a, and the colony generated from it, as 



seen two years and two weeks subsequent to the dissolution 

 of the Medusan roll, which crowned it when a fleshy bulb. 

 Nothing farther ensued while remaining under observation, un- 

 less continual gemmation of the young. 



II. Medusa. — Though I have nothing of real importance to add on 

 the history of the Medusarian race, for it is alike unprofitable to write 

 or to read of subjects imperfectly understood, still the accurate represen- 

 tation of a few species may prove acceptable to the naturalist. 



§ 1. Medusa aurita — Plate LI. Figs. 1-4. — This animal, some- 

 times sufficiently abundant in our seas, resembles a flattened bell or in- 

 verted saucer, six inches or less in diameter. The circumference is divided 

 into numerous lobes, with a fringe hanging downwards. Four appendages 

 descend from the under surface, which are much contracted in the morn- 

 ing, but relax as the day advances. One side of each is bordered by a 

 fringe, extending a little farther over the extremity. Perhaps there are, 

 in fact, only two appendages, each being cleft. 



The colour of this Medusa is variable, generally bluish, with many 

 red streaks, sometimes vivid. 



Four circular chaplets are seen near the convexity during summer, 

 being the ovaria, which come to maturity in August and September. 



The Medusa is incessantly collapsing during ascent in its vessel. It 

 always endeavours to gain the highest point, and will sometimes remain 

 there very long stationary. 



