THE CRUSTACEA OF NEW JERSEY 221 



triturating- food. Mandibles strong, always without palps. An- 

 terior maxillse normal, with two masticatory lobes, inner of 

 which with two or three brush-like set?e at tip. Posterior max- 

 illae peculiar, laminar, with only very slight indication of sub- 

 division into lobes. Maxillipeds not completely covering oral 

 parts, and terminal part more or less reduced. Marsupial pouch 

 in female formed of four pairs of broad lamellae issuing from 

 bases of second to fifth pairs of legs. Appendages of metasome 

 six pairs, five anterior respiratory in character, inner plate of 

 very delicate spongy structure and outer more strongly 

 chitinized, covers inner like an operculum. Sometimes oper- 

 cular plate has on two anterior pairs, more seldom on all pairs, 

 air-cavities or pseudo-tracheae. In male inner plate of second 

 and often of first pair, modified to serve for copulative pur- 

 poses. Last pair of appendages represent uropoda. usually 

 biramose, with rami uniarticulate, and project more or less 

 behind. 



Sars says "The forms of this tribe are generally found in 

 damp situations, beneath leaves, stones or timber, often in great 

 numbers, and feeding, it' would seem, on both animal and 

 vegetable matter. They all seem to avoid the full light of day, 

 and some forms even lead a true subterranean existence, in 

 which case the eyes are often rudimentary or wholly absent. 

 As to the respiration, it cannot properly be said to be ex- 

 clusively air-breathing in the same sense as in insects. It is 

 in fact to some extent branchial, and therefore a certain amount 

 of atmospheric moisture is indispensable to their existence. It 

 is for this reason that in very dry weather these animals seem 

 almost wholly to disappear, retiring more or less deeply into 

 crevices and hollows, wdiere some moisture remains."^ 



The following interesting extract, showing to some extent 

 the part these animals played in earlv therapeutics, was kindly 

 forwarded by Dr. Richard J. Phillips : 



Small beds of this thyme (Thymus citridonis) together with 

 mint are cultivated at Penzance in which to rear millepedes, or 



^ Crust. Norway, II, 1899. p. 154. 



