28 
Tank No. 1 
Siphonophora, are nearly all voracious robbers ; often swallowing animals, 
which one would suppose might easily overcome them. Inside the cavity 
of Beroe or in the pendant stalk of a Medusa are often seen small fish 
which the apparently delicate organism dissolves and digests. 
The Neapolitan forms include the barrel-shaped, comparatively tough 
Beroe (Fig. 32); the much more delicate form Callianira (Fig. 33); Eueharis 
(Fig. 34) consisting chiefly of water; and lastly the curious Venus’s Girdle, 
Cestus Veneris (Fig. 35). All of these attract the attention of the ob¬ 
server by the beads of light which seem to run over the body in 
various directions, displaying all the colours of the rainbow. This curious 
play of colours is caused by innumerable little plates, which are placed 
in vertical rows one above the other, and are moved up and down with 
great rapidity. By them the rays of light are reflected in such a way 
that the colours of the rainbow, which make up white light, appear se¬ 
parately. These plates, arranged in rows like the teeth of a comb, have 
caused these organisms to be called Ctenophora ("comb-bearers” j . 
EOHINODERMS. 
(Tank No. 1.) 
This group of animals comprises the Sea-urchins, Sea-stars, Sea- 
cucumbers, and Feather-stars. They are especially interesting to those 
not acquainted with marine life, for no 
member of the group occurs either in 
fresh water or on land. But the Echino- 
derms differ from most terrestrial and 
freshwater animals in a further way. If 
the lay mind be rather doubtful as to 
details of anatomical structure, it knows 
that, for example, birds, fishes and in¬ 
sects possess a head; that they are pro¬ 
vided with wings, fins or legs. They 
have a mouth, and eyes, and many other 
organs with which the least zoological 
of men is familiar from every day ob¬ 
servation; but how should he recognize 
these in a sea-urchin or in a starfish? 
These animals live, therefore they must eat; but where is their mouth? 
where are the limbs with which they grasp their prey? They live in the 
sea, but how do they move about? Do they crawl? Can they see and hear? 
transferred to the Aquarium; the smaller ones and the microscopic ones are 
caught with a net made of the finest silk-gauze, in the meshes of which they 
become entangled, and often of course damaged. — Most Ctenophora and Sipho¬ 
nophora, in spite of their size, are so delicate that they collapse immediately 
they are handled the least roughly, and can therefore not be taken out of the 
water. They only live a few days in the Aquariumalthough they are placed 
separately in large glass cylinders and seem to flourish very well at the com¬ 
mencement. — Most pelagic forms shine at night, some with a very strong light, 
and contribute largely to the Phosphorescence so frequently observed at sea. 
Fig- 36. Sphaer echinus granularis, 
Vo nat. size. 
