Salpid.e.- 



-MOLLUSCA.- 



-Bkyozoa. 



387 



Small creatures is by contiacting the whole boily, anJ 

 fiM'cing the water out at one or the other extremity. 

 Some other little Tunicaries have been found floating 

 on the surface of the ocean, in various parts of the 

 work), consisting of an ovoid-shaped body, terminated 

 by a long curved tail or swimming organ. They are 

 minute in size, from one-sixth to one-fourth of an inch, 

 and are rapidly propelled through the water by power- 

 ful vibrations of the long, curved, lanceolate, caudal 

 appendage. Tliese form the genus AprENDicuLAKiA. 

 Professor Forbes describes them as very nimierous at 

 limes, and appearing at a little distance, " as cloudy 

 patches of red colouring matter in the water." 



Family II.— PELONAIADiE. 



This family is composed of only one genus, Pei.onaia, 

 which contains two species, both of them very rare. 

 The animals are simple and unattached. The test is 

 more or less cartilaginous, smooth, or wrinkled, elon- 

 gated and cylindrical. The two orifices are not oppo- 

 site each other, but are both placed on the same plane 

 on two eminences on the anterior extremity. The 

 creatures live buried in mud, quite unattached to any 

 other body, and are extremely apathetic, presenting 

 scarcely any appearance of motion. 



BRYOZOA. 



Before drawing our history of the sub-kingdom 

 HfoHusca to a conclusion, we ought to mention the fact 

 that the large group of animals formerly arranged 

 amongst the Zoophytes, and known as the Bri/ozoa, 

 are now included within it; and that their proper place 

 in the zoological system ought to be immediately fol- 

 lowing the class Tunicata. The structure of the animals 

 belonging to the Bnjozoa is decidedly more mollusoan 

 than zoophytic ; and indeed were we only to imagine 

 the minute tentacula which fringe the oral orifice of 

 many of the Ascidian tunicaries to be greatly prolonged 

 and clothed with cilia, and the respiratory cavity to be 



contracted, wo should see the groat rcsoniManoe which 

 a Bryozoon, such asFliistra, has to a mollusk of tlio As- 

 cidian type. The nervous system of these little crea- 

 tures is not formed on the radiated type, but consii^ts 

 of a single ganglion placed between the two orifices, as 

 in the Tunicata. They have also a separate intestine, 

 which possesses an anal orifice; and there exist a 

 gizzard-like organ and a rudimental liver. Still, as in 

 almost all systems these animals continue to form 

 part of the class Zoophyta, we will postpone their 

 further consideration till wo come to treat of that 

 class. 



