Natural History of British Zoophytes. 329 



commonly do in the H. viridis. I have not observed more than one 

 young at a time, pullulating- 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 di versa tamen : " — 

 but the conviction of their permanent distinctness has been forced 

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

 confinement. Had, however, personal observation been awanting, the 

 same conclusion would have been willingly adopted on the paramount 

 authorities of Trembley and Baker, who bad very carefully studied 

 these creatures ; and Pallas speaks very decidedly to the same purport. 

 " Species Hydras a Linnaeo * pro varietatibus habitas, a Rseselio pri- 

 Dflum bene determinatas adoptavi, cum de trium priorum constantia, 

 propria me experientia certissimum reddiderit." — Elench. 29. 



3. H. FUSCA, brown or griseous ; inferior half of the body sud- 

 denly attenuated ; tentacula several times longer than the body. 



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

 3, fig. 11 J 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. 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. Pall. Elench. 



29 H. fusca, Lin. Syst. 1320. Ellis and Soland. Zooph, 9. Berk. 



Syn. i, 221. Turt. Gmel. iv. 691. Turt. Brit. Faun. 218. Stew. Elem. 



ii. 452. Lam. Anim. s. Vert. ii. 60. Bosc Vers, ii. 275 L'H. 



brune, Blainv. Actinol. 495. 

 Hab. Still waters in England, rare. In a pond at Hackney, Mr 

 John Ellicot. t 



" The tails of these are long, slender and transparent, and when 

 placed before the microscope, a long straight gut may plainly be dis- 

 tinguished passing from the body-part or stomach to an opening at 

 the end thereof. These are rather lighter coloured than the former, 

 (H. vulgaris,) and have seldom more than six or eight arms, but those 

 capable of great extension." — Baher. 



Baker reckoned that his English exemplers were of a sort different 

 from those he had received from M. Trembley, but the only apparent 



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



t Elected F. R. S. Oct. 26, 1 738 ; and the author of several papers on sub. 

 jeets in Natural Philosophy, published in the Phil. Trans, between the )'ears 

 1745 and 1750. He was a watch-maker, and died in 1772. 



