1922 ] 
Chamberlin — A New Chilopod from Mexico 
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A NEW SCHENDYLOID CHILOPOD FROM MEXICO. 
By Ralph V. Chamberlin, 
Museum of Comparative Zoology, Cambridge, Mass. 
The type of the interesting new chilopod described below was 
taken by Dr. Wm. M. Mann several years ago at Guerrero Mill, 
Hidalgo, Mexico. It represents a new genus related to the 
North American genera Nyctunguis Chamberlin and Nesonyx 
Chamberlin in having ventral pore areas in the anterior region 
and in possessing a well developed claw on each anal leg. It 
differs from these genera in having only a single coxal pore on each 
side. In this respect it agrees with the West African Mesos- 
chendyla of Attems,but the latter genus has no claw on the anal 
legs. 
Mexiconyx, Gen. nov. 
Claw of the second maxillae pectinate. Labrum with median 
arc bearing true teeth which are well chitinized and have dis- 
tinct roots. Mandible with a single pectinate lamella. Ventral 
pores present on sternites of the anterior region. A single coxal 
pore on each side, this simple or homogeneous. Anal legs 
terminating in a normal claw. 
Genotype. — M. hidalgoensis, sp. nov. 
Mexiconyx hidalgoensis, sp. nov. 
Head longer than wide, widest in front of middle; anterior 
margin convex or very obtusely subangular, the caudal margin 
straight and the lateral margins convex and converging caudad 
from in front of middle. Prebasal plate not exposed, the head 
well overlapping the basal plate, the exposed portion of which is 
rather short. Claws of prehensors when closed surpassing the 
head, reaching to the end of the second antennal article or nearly 
so. Joints of the prehensors unarmed within. Prosternum also 
unarmed; without chitinous lines. Labrum rather deeply ex- 
cavated at the middle and bearing in the type twenty-two 
teeth of which those of the median arc are more strongly chitinized 
and differentiated; five teeth at the crest of the arc are directed 
ventrad. Dentate lamella of mandible presenting six or seven 
