130 Selections. [No. 7, new series * 



it and the rest of the body. In all other respects the three classes 

 that compose the sub-circle of the Molluscoids differ altogether, 

 so that we must consider their peculiarities in the respective 

 classes, which are : — 



1st. The " moss-animals" [Bryozoa) distinguished by their 

 resemblance to polyps, their seizing arms and their social form ; 

 a few genera inhabit fresh water. 



2nd. The " Rib-medusae" (Ctenophora) with rows of swim- 

 ming in the water and jelly-like bodies ; these all live in the sea : 

 and 



3rd. The " Mantle-animals" (Funicata) of highly un symme- 

 trical build, enveloped in a broad mantle, and without peculiar 

 organs of motion ; these all live in the sea. 



Class Bryozoa. 



These animals so much resemble polypi in their outward growth 

 that they have often been confounded with them, but their inter- 

 nal structure will be found to be altogether different. 



The Bryozoa are little polyp-like animals which form colonies, 

 and are always surrounded by cells into which the animals can 

 retreat, partially or entirely. The cells are sometimes horny or 

 pliable like parchment, sometimes soft and jelly-like ; sometimes 

 they stand on their own stalks which rise out of a network of 

 tubes, which spreads itself by runners in the same way that many 

 plants creep along the ground, but then rises and branches out. 

 But in most cases and particularly in the sea Bryozoa the cells are 

 of a calcareous nature, and then resemble the forms of many 

 corals, possessing however hairs and horns which the coral-polyp 

 never has. Moreover in some cases the Bryozoa cells are fur- 

 nished with a covering which can be closed when the animal has 

 retreated into its case ; and even when the cells are leathery, the 

 fore-end can be contracted so as to enclose the animal completely. 



In some of the genera living in the sea ( Cellularia, Bicellaria, 

 Flustra and Telegraphina) very strange organs Tiave been disco- 

 vered, the use of which is still quite unknown. They are seizing 

 organs which look not unlike a bird's head: — see fig. 7, plate v., 

 possessing a very strong upper and a very thin lower pincer. 



