578 THE MICROSCOPE. 



stitutes one of the chief points of interest in the organiza- 

 tion of Tomopteris." 



Not solely in this class, but in that of the Annelida 

 generally, does much interest attach to the developmental 

 period. Most of them come forth from the egg in a con- 

 dition so closely resembling the cililated gemmules of 

 polypes, that competent observers have been known to 

 mistake them for animals of a lower class ; fortunately a 

 few hours' careful watching is sufficient to dispel the 

 illusory belief, and the embryonic globular shapeless 

 mass is seen soon to change its form ; segmentation takes 

 place, and the various internal organs become more aud 

 more developed ; eye spots appear, and the young animal 

 assumes the likeness of its parent. 



The Actinotrocha, even in the adult state, in many parti- 

 culars resembles the "bipinnarian larva of the star-fish." 

 Its long body is surmounted by a head, or mouth, around 

 which is placed a number of ciliated ventacula : they are 

 not only employed for feeding purposes, but also for 

 enabling it to swim about ; and in this particular, accord- 

 ing to Dr. A. Schneider aud other competent authorities, 

 it is quite remarkable. 1 Dr. Carpenter tells us that he 

 has captured these free-swimming Annelids among other 

 marine animals by the careful use of the " stick-net." 



iD See Ann. Nat. Hist. vol. ix. 1862, p. 4S8. 



