526 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



ard's figure of the last species (Am. ISTat., v, p. 749) we find that there 

 are but seven joints represented, which is in agreement with what we 

 find in TricJiopetalum, Zygonopus, Craspedosoma, and Lysiopetalum ; and 

 in the case of the two first, Professor Cope's virtual assignment of them 

 to Spirostreplion makes the number of joints in their antennae doubtful. 

 Trichopetalum Harger, might probably have been more closely defined 

 as to its generic characters, since those given by its author would not 

 define it from Zygonopus, and it differs only from S. (8.) copei in having 

 eyes, from Craspedosoma in having free sterna, though the latter may 

 have free sterna too. Mr. Harger, however, admits the diffiuclties which 

 beset him, at page 119, in a foot-note (Am. Jour. Sci., iv, 1872). 



While examining some living specimens of Trichopetalum lunatum 

 under the microscope, about a year since, I observed that the respira- 

 tion of the animal appeared to be conducted in a most singular man- 

 ner. The air seemed to be drawn in under the lab rum and in some way 

 to enter the dorsal cardiac sinus as bubbles, which could be traced for 

 some distance, more than half the length of the animal, as they trav- 

 eled slowly backwards, until they disappeared over the opaque mass of 

 ingested food contained in the intestine. These bubbles of air always 

 passed backwards. It may have been that they passed backwards in- 

 sile of the intestine, but the impression I got was that they were trav- 

 eling through the cardiac sinus or dorsal heart of the animal. This 

 circumstance may explain why it is that there are no pores on the side 

 of the body, though it is true that the lateral pores of millipeds are 

 usually foramina repuguatoria, and have nothing to do with the trachea 

 or respiratory apparatus. This raises the question whether our Lysi- 

 opetalidce are not distinguished from other forms in some more impor- 

 tant way than has been hitherto supposed. 



The species which have been described are the following, though it is 

 to be understood that they are only given as a list for reference; no ar- 

 rangement is yet possible and none is attempted : 



1. Spirostrephon lactarius Say, Wood (Trans. Am. Phil. Soc, n. s., 



xiii). Art. Myriap. of N. Am., p. 192, with synonomy; Cope, Proc. 

 Am. Phil. Soc, xi, p. 179. 

 Sabitat.: — Eastern United States. 



2. S. cjesioannulatus Wood, op. cit., p. 194. 

 Habitat. — Allegheny County, Pennsylvania. 

 Length 1 inch. 



3. PsEUDOTREMiA CAVERNARUM Copc, Proc. Am. Phil. Soc, xi, p. 179, 



18C9; Cope, Proc. Am. Ent. Soc, iii, p. 67, 1870; Packard, Am. Xat., 



V, p. 749, 1871. — Spirostrephon cavernarum Cope, Am. Nat., vi, p. 



414, 1872. — P. cavernarum Harger, Am. Jour. Sci., iv, pp. 118, 119. 



1872. 

 Habitat. — Caverns in Virginia and Indiana. 

 Length 11 lines. 



