88 Proceedings of the Biological Society of Washington. 



Considering the locality of Mr. Bethel's Peripatus, at sea level on the 

 Atlantic side of Guatemala, 500 miles from the locality of P. biolleyi, we 

 should expect it to be a distinct species. It differs from biolleyi strikingly 

 in color, and slightly in the teeth. It also certainly seems to have the 

 papilte more irregularly placed, quite, in fact, as in the otherwise diverse 

 P. isthmicola. This character is not so satisfactory as one could wish, 

 owing to a certain lack of uniformity in the papillse of different parts of 

 the body. 



On the other hand, the peculiar accessory denticles of the inner blade 

 of the mandibles are of the biolleyi type, and no other Peripatus has any- 

 thing very like this. The same may be said of the arrangement of foot- 

 pads and nephridial tubercles. Bouvier notes that the original P. biolleyi, 

 from near San Jose, was yellowish red (jaune roux), whereas the speci- 

 mens from a lower altitude on the Pacific slope were marked like P. 

 trinitatis, with a series of dorsal losenges. Is it not probable that there 

 are two races in Costa Rica, one belonging to the highlands, the other to 

 the low country on the Pacific side? Mr. Bethel's animal presumably 

 represents a special race or subspecies of the tropical Atlantic coast-region, 

 which may extend southward as far as Costa Rica. 



Mr. Bethel's specimen was in process of moulting, and the new skin 

 exposed was consequently very fresh and well colored, so that there is no 

 doubt concerning the natural colors of the animal. 



