124 ANTHOZOA HYDROIDA. 



a more gracile form. Its colour is a dilute olive-green with paler 

 tentacula, which are considerably longer than the body, and hang 

 like silken threads in the water, waving to and fro without as- 

 suming that regular circular disposition which they commonly do in 

 the H. viridis. I have not observed more than one young at a time, 

 which pullulated from near the middle of the body ; and after this 

 has attained a certain growth, the polype has the appearance of 

 being dichotomously divided. 



Dr. Fleming's Hydra vulgaris, Brit. Anim. 553, embraces this and 

 the preceding, as well as the following species, which are considered 

 the mere variations of one protean original : 



" Facies non omnibus una, 

 Nee diversa tamen :" 



but the conviction of their permanent distinctness has been forced 

 upon me by a long continuous observation of individuals in a state 

 of confinement. Had, however, personal observation been wanting, 

 the same conclusion would have been willingly adopted on the para- 

 mount authorities of Trembley and Baker, who had very carefully 

 studied these creatures ; and Pallas speaks very decidedly to the 

 same purport : " Species Hydrse a Linnseo* pro varietatibus ha- 

 bitas, a Roeselio primum bene determinatas adoptavi, cum de trium 

 priorum constantia, propria me experientia certissimum reddiderit." 

 Blench. 29. 



4. H. OLIGACTIS, brown or griseous ; inferior half of the 

 body suddenly attenuated ; tentacula several times longer than 

 the body. 



VIGNETTE, No. 27. PAGE 120. 



Polypes a long bras, Tremb. Mem. pi. ] , fig. 3, 4, 6 ; pi. 2, fig. 1, 3, 4 ; pi. 3, fig. 1 1 ; 

 pi. 5, fig. 1-4 ; pi. 6, fig. 3-7, 9, 10 : pi. 8, fig. 8, 11 ; pi. 9. copied in Adams 

 Micros. 399, pi. 21, fig. 7, 8 ; pi. 23, A. B ; pi. 24, A. B, fig. omnes. Rosel 

 Hist, der Insect. Polyp, iii. pi. 84-87. Cuv. Reg. Anim. iii. 295. Long-armed 

 Fresh- water Polype, Ellis Corall. xvi. pi. 28, fig. C. (the tentacula shortened, for 

 the conveniency of introducing them within the size of the plate). Second sort 

 of Polype, Baker Polyp. 18, c. fig. Hydra oligactis, Pott. Elench. 29. Ehrent,. 

 Corall. des roth. Meer. 68. H. fusca, Lin. Syst. 1320. Encyclop. Method. Vers, 

 pi. 69, fig. 1-9. Pecs' 1 Cyclop Vermes, pi. 5, fig. 3. Ellis and Soland. Zooph. 9. 

 Blumenb. Man. 275. Lam. Anim. s. Vert. ii. 60. Hydra verrucosa, Templeton in 

 Mag. Nat. Hist. ix. 418, fig. 57. Allman in Ann. Nat. Hist. xiii. 328. 



* In the 10th edit, of Syst. Nat. p. 816, under the name of Hydra Polypm. 



