EXAMPLE OF CONNECTION BETWEEN SUB-KINGDOMS. 63 



charge, a. Now, there are certain species of Polypes (termed 

 Bryozoa), of which one form is shown in Fig. 24, that have a 



c b a 



FIG. 24. PLUMATELLA ; a, NATURAL SIZE ; b, A GROUP ENLARGED ; c, ANAL ORIFFCB. 



structure almost identical in all its most obvious characters. 

 The principal apparent difference is in the presence, in these last, 

 of two or more arms, which are covered with cilia (ANIM. 

 PHYSIOL. 117)? by whose vibration the currents are established, 

 that convey food to the mouth. In the Tunicata, however, 

 the mechanism is essentially the same ; but the cilia are dis- 

 posed in the lining of the interior chamber. So far, then, it 

 would appear that the resemblance is so great, as to permit 

 these two groups to be associated in one class, the place of which 

 would be at the head of the Polypes ; and this has actually been 

 done by M. Milne Edwards, a Naturalist of great eminence, 

 who has given much attention to both groups. But there are 

 certain considerations which lead the Author to the belief, that 

 the Tunicata are still to be ranked among the Mollusca, and the 

 Bryozoa among the Polypes ; the principal of which are these. 



