Hydra. 
Z. HYDROIDA. 
95 
gating much more abundantly, furnished a good supply of what was 
evidently a favourite food. 
2. H. vulgaris, orange-brown or sometimes oil-green ; body 
cylindrical ; tentacula 7-12, as long or longer than the body . 
Plate I. 
Polypes de la seconde espece, Tremb. Mem. pi. 1, fig. 2, 5 ; pi. 2. fig. 2 ; 
pi. 6. fig. 2 and 8; pi. 8. fig. 1 — 7 ; pk -it), fig. 1 — 7 ; pi. 11, 12, 13. 
figs. omn. partly copied in Adams , Micros, 399, pi. 21. fig. 6 Hydra 
vulgaris, Pall. Elench. 30. Ellis in Phil. Trans, lvii. 430. Ellis and 
Soland. Zooph. 9 H. grisea, Lin. Syst. 1320. Mull. Zool. Dan. 
Prod. 230, No. 2784. Verm. i. ii. 14. Ure's Rutherg. 233. Berk. 
Syn. i. 222. Turt. Gmel. iv. 692. Turt. Brit. Faun. 218. Blumenb. 
Man. 295. Stew. Elem. ii. 452. Lam. Anim. s. Vert. ii. 60. Bose , 
Vers ii. 275. Stark, Elem. ii. 443. Templeton in Mag. Nat. Hist. ix. 
418 H. brunnea, Templeton, loc. cit. 417. fig. 56 First sort of 
Polype, Baker, Polyp. 17. c. fig L’Hydre commune, Blainv. Acti- 
nol. 495. 
Hob. Weedy ponds and slowly running waters Probably common 
in all parts of the kingdom. 
On comparing the descriptions of the authors quoted above, I am 
led to conclude that this species is either subject to much variety, or 
that two species have been confounded together, and given rise to a 
discrepancy which seems otherwise irreconcileable. My own expe- 
rience inclines me to the latter supposition, but since I have had no 
opportunities of making observations on specimens from different and 
distant localities, I deem it more prudent to indicate what appear to 
be two species as only varieties of the vulgaris , until the point can 
be settled by more leisured naturalists. 
Var. a. aurantia, light reddish-brown or orange-coloured ; tenta- 
cula not longer than the body. Fig. 2. 
Var. b. grisea, light olive-green ; tentacula paler and longer than 
the body. Fig. 1. 
The first is by much the commoner, and does not exceed the H. 
viridis in size, which it resembles also in its habits and form. It is 
always of an orange, brown, or red colour, the intensity of the tint 
depending on the nature of the food, on the state of the creature’s 
repletion, becoming even blood-red when fed upon the small crim- 
son worms and larvae which usually abound in its haunts.* The ten- 
* “ I have found a bright red Hydra rather abundant on Putney Heath, near 
London. It does not much differ, except in colour, from the green one.” J. 
E.Gray in lit. May 6, 1833. — See Trembley’s Mem. p. 47, and 128. 
