HYDRA 



Fig. 73. — Hydra. 



L A, two living specimens of H. mridis attached to a bit of weed. The larger 

 specimen is fully expanded, and shows the elongated body ending distally in the 

 hypostome (Jiyp), surrounded by tentaeles if), and three buds {bd.^, hd,^, bd.^) in 

 different stages of development ; a small water-flea {a) has been captured by one 

 tentacle. The smaller specimen (to the right and above) is in a state of complete 

 retraction, the tentacles (t) appearing like papillse. 



f B, H.Jiisca, showing the mouth (inth) at the end of the hypostome {hyp), the 

 circlet of tentacles {t\ two spermaries (j/j/), -and an ovary (pvy) 



C, a Hydra creeping on a flat surface by looping movements. 



D, a specimen crawling on its tentacles. (From Parker's Biology : C and D after 

 W. Marshall.) 



hypostome {hyp), at the apex of which is a circular aperture, 

 the mouth imth). At the junction of the hypostome with 

 the body proper are given off from six to eight long delicate 



