found in the Northumberland Lakes. 289 
Figs. 3, 4. Two much-enlarged views of the same before development of 
Fig. 5. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
a 
ig. 
Fig. 
Fig. 
Fig. 
Fig. 
er 
the sperm-vesicles. 
Two highly magnified views of the terminal portion of the 
tentacle, exhibiting nodular enlargements, @, and terminal bulb 
or nodule, 0b. 
. Egg after attachment to some foreign body much magnified, ex- 
hibiting chorion : a, a, a, a few of the mucus-globules contained in 
vesicles adhering to the egg. 
A few of the same vesicles containing mucus-globules more highly 
magnified. 
Puate VII. 
. Hydra much enlarged, exhibiting development of ova: a, basal 
portion of tentacles; 6, mouth; c¢, c, sperm-vesicles ; d', ovum 
considerably advanced; d, ovum just before it bursts through its 
envelope, e. 
. Much-enlarged view of egg as it appears immediately after it has 
burst the envelope : a, eg; b,b, margins of envelope; c, c, por- 
tions of the animal. 
. A portion of Hydra much magnified, exhibiting the egg when ready 
to separate from parent: a, portion of the animal; 0, egg; ¢,¢, 
mucus-globules as they at first appear; d, pedicle attaching egg 
to parent; e, e, contracted margins of envelope. 
. Enlarged view of Hydra much contracted with egg attached, ex- 
hibitmg anal orifice : a, mouth ; 0, anal orifice as seen through the 
substance of the adhesive disc ; ¢, feces passing out of same; d, 
sperm-vesicle ; e, egg with undulated margins ; f, pedicle attaching 
same to parent ; g, contracted margin of envelope. 
Sperm-vesicle much enlarged of the Hydra from the Northumber- 
land lakes : a, gland-like body within the base of same ; 0, apex of 
same containing spermatozoa; ¢, c, a portion of surface of animal. 
. Sperm-vesicle much enlarged of H. viridis: a, gland-hke body 
within base of vesicle ; 6, apex of same containing spermatozoa ; 
c, c, surface of animal. 
- Much-enlarged view of portion of tentacle of the flesh-coloured 
Hydra as seen in the compressor, exhibiting captor organs and 
organs of touch imbedded in the nodular enlargements : a, organs 
of touch; 5, captor organs. 
. Two of the organs of touch greatly magnified, exhibiting inner and 
outer vesicles and cilium. 
. Greatly enlarged view of retracted captor organ: a, outer vesicle ; 
b, arrow-head with barbs depressed; c, membranous stalk of 
same ; d, inner or lining membrane doubled down upon itself. 
10. Captor organ exserted: a, outer vesicle ; b, inner or lmimg mem- 
brane ; c, membranous stalk supporting arrow-head with the 
three barbs, c', elevated; d, filament passing out of the pomted 
extremity of arrow-head. 
11. Two enlarged views of elliptical sacs with filaments supposed to 
be poison-organs cast from captor organ. 
12. Two of the spermatozoa highly magnified from sperm-vesicle of 
flesh-coloured Hydra. 
Ann. & Mag. N. Hist. Ser. 2. Vol. v. 19 ° 
