The Craspedosomatidm of North America. 15 



and that the animal maj^ have the power of moving them at will, 

 and the desirability of being thus able to move them becomes 

 evident if they are supposed to be spinning organs, while it 

 would be useless if they have no special function. 



Sense-Organs and Problematical Structures. 



In the course of the s^'stematic examination of the different 

 forms it was necessary to mount above a hundred microscopic 

 slides. These gave opportunity for the examination of the more 

 minute structures of the animals, sometimes under tolerably favor- 

 able conditions. Following are noticed briefly the structures 

 which came to our attention. Some of them seem not to have 

 been previously recorded, and our notes may be of use when a 

 histologic study of the group is attempted. 



I. — Antennae. 



On the antennse are several types of more or less hair-like struc- 

 tures, all of which may prove to be sense-organs. 



1. The So-called Olfactory Cones (figs. 61 and 190). — These 

 are well developed in all the species, the number being always 

 four, as is the case in most Diplopoda. We have counted hun- 

 dreds of specimens, including representatives of all the families, 

 and have never found less than four. There are more than four 

 cones in Glomeridse, some species of Spirobolus, and a genus of 

 Polydesmidae from east Africa. The reports of one, two and 

 three cones can be paralleled by the carelessness displayed in count- 

 ing the segments of Chilopoda. 



The cones of Craspedosomatidse appear to differ from those of 

 other families only in being more slender, more like a wine bottle 

 in shape, and with longer bases. 



2. Hairs of Ordinary Form. — Such may occur on other parts 

 of the body, and it is possible that all may have more or less 

 of tactile function. According to Sazepin's diagrams of the an- 

 tennse of lulidse and Pol^'desmidse these hairs have neural con- 

 nection, and the same conditions seem to obtain in sections of the 

 antennse of Conotyla fischeri. 



3. At about the middle of the seventh joint, and pointing lat- 

 terad when the antenna; are extended, is a solitary, rather slender, 

 mammillate-conic, transparent protuberance, narrowed at the tip 

 and produced into a long, ver^'^ slender, and exceedingly fine- 



