The Graspedosomatidse of North America. 19 



to conjecture, unless the}'' are spinning organs, as suggested in 

 another place. 



In common with Polydesmidse the anal valves of this family 

 are provided with slender bristles, but there are always three pairs 

 instead of two, the constant number in Polydesmidse. 



The preanal scale has two slender bristles, as in Pol,ydesmidse. 

 These are of the same form as those of the anal valves, have en- 

 larged bases and may prove vto be tactile organs ; at least this 

 would be a reasonable inference in case neural connection can be 

 proven. 



YI.—Legs. 



The legs are increasinglyhirsute distad, some of the hairs being 

 especially long and with enlarged bases, perhaps tactile organs. 

 On the inner edge of the last joint of the first and sometimes of 

 the second legs is a pectinate row of stout hairs or bristles; it may 

 be these are of use in feeding or in cleaning the face and antennae. 



The first legs have the claw large, and two. distinct supple- 

 mentary claws. The other legs usually have one supplementary 

 claw. The other structures of the legs are more properly to .be 

 noticed under the head of sexual characters. 



On the claw of all the legs of Gonotyla Jischeri is a peculiar 

 hair, which we have not found on other species. The hair in 

 question rises from the inferior groove about midway between 

 base and apex, and lies closel}^ appressed to the claw, beyond 

 which it extends as an exceedingly fine, frequentl}^ flexuous fila- 

 ment, needing careful observation to be seen with a quarter-inch 

 objective. When the animal is walking this hair necessarily 

 comes first in contact with the ground and seems conveniently 

 located for a tactile organ. It appeal's A^ery remarkable that the 

 other species have no similar structure, but a careful search has 

 failed to find it. 



Yll.^Secondary Sexual Characters. 



These are, as in other families of Diplopoda mostl}^ confined to 

 modifications of the anterior male legs. We give here a list of 

 such modifications, not including those of the ninth male legs 

 which are described under the different genera and species. 



1. Body of. males stouter and broader, especialhT^ segments six 

 and seven, than that of females. This is not always noticeable, 

 but is very evident in Cleidogona. 



