NANOMIA. 79 



all the lower members of the stock. The shields share in this 

 general nourishment of the compound body by means of chymif- 

 erous tubes extending toward the outer surface > and opening into 

 the cavity of the stem. The mouth of this Hydra is very flexible 

 (Fig. Ill), expanding and contracting at the will of the animal, 

 and sometimes acting as a sucker, fastening itself, leech-like, on 

 the object from which it seeks to draw its sustenance. (See Fig. 

 111.) The tentacles attached to this set of Hydrae are exceed- 

 ingly long and delicate. They arise in a cluster at the upper 

 and inner edge of the Hydra, just at its point of juncture with 

 the stem, and being extremely flexible and contractile, their 

 long tendril-like sprays are thrown out in an endless variety of 

 attitudes. (See Fig. 115.) Along the whole length of this 

 kind of tentacle are attached little pendent knobs at even 

 distances ; Fig. 112 represents such a knob greatly magnified, 



Fig. 112. 



and absolutely paved with lasso-cells, the inner and smaller ones 

 being surrounded by a row of larger ones. 



The second set of Hydrae (Fig. 113), are also open-mouthed, 

 corresponding with those described above, in everything except 

 the tentacles, which are both shorter and thicker, and are coiled 

 in a corkscrew-like spiral. These are thickly studded for their 

 whole length with lasso-cells. (See Fig. 113.) 



In the third and last set of Hydras (Fig. 114), the mouth 



Fig. 112. Magnified pendent knob. 



Fig. 113. Medusa with corkscrew-shaped tentacles. 



