96 
Z. HYDROIDA. 
Hydra. 
taeula in all my specimens have never exceeded the length of the 
body, are usually seven or eight in number, and taper to the point 
insensibly. Every part of the body is generative of young, which 
may frequently be seen hanging from the parent at the same time in 
different stages of their growth. Baker’s figure represents this va- 
riety very well. 
The second is a larger animal and comparatively rare, less sensible 
to external impressions, and of a more gracile form. Its colour is a 
dilute olive-green with paler tentacula, which are considerably long- 
er than the body, and hang like silken threads in the water, waving 
to and fro without assuming that regular circular disposition which 
they 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 dicliotomously divided. 
Dr Fleming’s Hydra vulgaris , Brit. Anim. 553, embraces this 
and the preceding, as well as the following species, which are consi- 
dered the mere variations of one protean original 
“ Facies non omnibus una, 
Nec 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 of 
confinement. Had, however, personal observation been wanting, the 
same conclusion would have been willingly adopted on the paramount 
authorities of Trembley and Baker, who had very carefully studied 
these creatures ; and Pallas speaks very decidedly to the same pur- 
port. 4 4 Species Hydrae a Linnaeo* pro varietatibus habitas, a Raese- 
lio primum bene determinatas adoptavi, cum de trium priorum con- 
stants, 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 . 
Vignette, No. 11, page 93. 
Polypes along bras, Tremb. Mem. pi. 1. fig. 3, 4, 6 ; pi. 2. fig. 1, 3, 4; pi. 
3, fig. 11 ; 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. 
In the 10th edit, of Syst. Nat. p. 816, under the name of Hydra Polypus. 
