Plate Io. 
POLYPI. 
In outward appearance the Polypi approach very closely to the Actinia. The lower 
part of the body is in most cases firmly attached to some object, while the upper end 
spreads itself out like a bell, and bears some 8 or 9 short arms disposed around the wide 
mouth and furnished with an ample number of tentacles. 
1. The Lucernaria Auricula is found in the Northern Seas attached to seaweed by a 
narrow disk, from which it expands into a broad octagonal figure with a bundle of ten- 
tacles at each angle and a quadrangular mouth in the centre. This pretty little creature 
is only one inch in height. 
The family of the Pennatulide, or Sea-feathers, includes only a few varieties, most of 
which are found in European waters. Whatever be the general form, one of the extre- 
mities is always devoid of polypi, while the polypiferous portion resembles expanded barbs 
and exhibits more bilateral symmetry than is seen in the other Polypiaria. Most of these 
animals are unattached, and float in the water or stick themselves into the sand or mud. 
2. The Pennatula Phosphorea is from 2 to 4 inches in length, and is met with on 
the Scottish coast. It is nocturnal in its habits, and when touched emits a transitory 
phosphorescent gleam. 
The Tubularia have fine straw-like stems of a horny consistence, which are firmly at- 
tached to stones or mussels, the upper ends bearing small polypi, which are free and non- 
retractile, and adorned with a bunch of tentacles. They are only found in deep water. 
3. The Tubularia Indivisa is found on the coasts of the North Sea, generally in 
groups of 30 or 40 stems about 5 or 6 inches in height. The bright red polypi bear a 
double row of tentacles which are constantly in motion. — 
Among those genera of the Polypi, wiseh distinguish themselves by the formation of 
their calcareous stems, the Madrepora occupy an important place. These formations some- 
times resemble a widely branching tree, while in some genera the growth is ragged and 
irregular, the extent however being so great as often to form a regular reef of rock. 
4. The Madrepora Abrotanoides is found in the Pacific, and often grows so pro- 
fusely as to form islands. 
5. The Millepora Alcicornis of the Antilles more resembles sea- weed in its irregular 
shape. The polypi cells distributed over the whole of its surface do not project, but 
form little cavities in its substance. 
6. The Tubipora Rubeola, or Organ-Coral, is distinguished for the beautiful grouping 
of its brilliantly tinted stems, which do not grow together laterally, but stand independently, 
like the pipes of an Organ, and are merely connected by lateral ribs at intervals. This 
beautiful species is found among the islands of the Atlantic. 
The Sertularia attach themselves to seaweed, mussels or other objects, the upper end 
extending itself in many branches with cells, arranged alternately or in pairs obliquely on 
the stem, which cells open upwards and contain the polypi. 
7. The Sertularia Tamarisca, a very pretty species, is commonly found on the 
English and Irish coasts. 
8. The Corallium Rubrum, the Common Red Coral of the Mediterranean, grows like a 
little tree firmly attached to the rugged rocky bottom at a depth of from 40 to 100 fathoms, 
and is very abundant on the coast of Algiers, where it is fished for with long drag-nets and 
exported to be worked up into necklaces and other ornaments. The delicate white polypi, 
decorated with a cluster of tentacles, are irregularly distributed over the red stems. 
The genus Gorgonia is of a horny substance and slightly flexible notwithstanding the 
calcareous corpuscules with which it is studded. It sometimes assumes the form of a tree, 
and at others appears as network. 
9. The Gorgonia Verrucosa, a delicate species, is found in the Mediterranean. — 
The Hydra is the only genus of fresh-water polypi. They are found all over Europe- 
attached to aquatic plants, though they can easily shift their quarters if so disposed. 
They are very diminutive creatures and have 6 or 8 feelers surrounding the mouth, which 
they use to numb and thus overcome their prey with. Reproduction is effected by means 
of external germs, which are developed at the lower end of the mother-plant, detaching 
themselves when fully developed. 
10. The Hydra Viridis, and 11. The Hydra Fusca are commonly found growing on 
plants in ponds and ditches. — 
The very varied genus of the Bryozoa, owing to the similarity manifested in many 
respects to the Ascidians, has been classed by modern zoologists with the Molluscoidea. 
It is divided into two subfamilies, — the marine, with horny cells, and the fresh-water, with 
soft cells, — both of which are found in very extensive colonies. 
12. Represents the Cristatella Mucedo, a fresh-water species. 
