38*2 SYNOPTIC COLLECTION. 



resemblances in internal structure, place Peripatus to-day 

 among the articulated animals with jointed appendages. 



Its worm-like affinities together with its scattered spira- 

 cles and the single pair of jaws seem to take Peripatus 

 from the Myriapods probably its nearest allies and 

 to place it in a class by itself. 



It may be that Peripatus is the survivor of a primitive 

 type which, however, has lost some of its primitive char- 

 acters, and become more or less specialized by the suppres- 

 sion of parts. The loss of segmentation and the obscure 

 jointing of the legs would point to this conclusion, while 

 the power possessed by Peripatus of bringing forth its 

 young alive is an indication of specialization of structure. 

 The retention of paired nephridia suggests its possible 

 remote origin from some worm-like form, while the pos- 

 session of tracheae proves that it is far removed from the 

 Worms and is doubtless near the Myriapods and Insects. 



MYRIAPODA. 



Section 14 (in part). 



"The relations of ancient to modern forms of life," 

 says Scudder, 1 "prove far more important and interesting 

 in the myriopoda than in either the arachnida or the 

 hexapoda." 



This eminent authority points out that the embryology 

 of living forms of Myriapods is inadequate to explain the 

 origin of the complex structure of the segments, and that 

 we must look to the palaeontologic record for light on this 



'The Geological History of Myriopods and Arachnids, Psyche, 

 IV, Jan.-March, 1885, p. 245 ; see also Bull. U. S. Geol. Surv., no. 

 31, 1886. 



