52. 



to the otiter labial palps, appears as an outgrovrth from the body 

 wall. The palps have not attained any considerable development 

 in any of the embryos reai'ed from eggs. 



The gajiglia are all distinct in T/ifliole mounts as well 

 as in sections. At first the cerebral ganglia are much larger 

 than either of the others, figure 33, but the pedal ganglia grow 

 rapidly, and soon come to equal if not to exceed them in size, 

 figure 36. No division into cerebral and pleural ganglia has 

 been observed. 



GENSRAL aSMASKS. 

 ANATOMY.. 

 Since Mitsukuri's ^^'^j paper appeared in October 1381, 



much has been ivritten on the anatomy, and itc oignifl e aao O' , of 



( 1 5) 

 members of this group. Pelseneer ^ has called attention to 



certain characters, in support of the supposition that the group 



is primitive. Possibly influenced by tZ-ie desire to make the case 



as strong as possible, he has allowed some errors to creep in. 



Thus he says on page 272 : 



" The least specialized 1 ame 1 1 ibran chs : In demonstrate 



ing the ph3'-i ©genetic development of the gills, part 2, IV, 6, 



p. 246, I have shown that the most primitive of t}ies<i organs are 



