Apeil — sept. 1858.] Order Radiata. 



131 



These organs are in constant swinging motion like a pendulum, 

 and the pincers are opened and shut from time to time which must 

 be the result of a muscular action. Apparently these organs are 

 analogous to the Pedicellaria of the Echinodermata, for like them, 

 their motion continues after the death of the animal. In the ge- 

 nus Telegraphina, instead of these organs there are long stiff 

 threads on the edge of the cell, which are also in constant swing- 

 ing motion. 



Eyes and ear-bladders are wanting altogether ; the spots which 

 in some genera have been taken for eyes, are not connected with 

 vision. 



In all the Bryozoa there is to be found at the upper end of the 

 body a circle of actively moving seizing threads, each of which is 

 hollow, and connected with the cavity of the inside of the body, 

 and in which the fluid which fills the body is driven up and down. 

 The seizing threads are set with delicate hairs, which by the ed- 

 dies they occasion in the water drive the food, little animals, &c. 

 towards the mouth which lies in the middle of the circle : — they 

 may be useful also as a breathing apparatus, which would other- 

 wise be quite wanting in the Bryozoa. 



The polyp stocks of the Bryozoa, which are mostly very small 

 and inconspicuous, are found in great numbers both in fresh and 

 salt water, on all possible substances under waters. They are 

 numerous too in the different strata of the earth especially in the 

 pur as sic formation. 



This class is divided according to the position of the feelers into 

 2 orders. In the " circle-whirlers" (Stelmalopoda) the feelers 

 stand in a circle round the mouth ; all the genera which belong to 

 this order live in the sea. It is they alone that possess calcareous 

 dwellings, and therefore are found in a fossil state. According to 

 this and the arrangement of the cells, the order is divided into 4 

 families. 



1st. The " Thousand-whirlers" {Mitleporida) which have cal- 

 careous, generally finger shaped branching polyp-stocks, in which 

 the simple round cells are so confused, that at most a part of the 

 upper opening appears free on the surface. These animals are 



