680 CHILOGNATHA. 



1863. Plate vi, fig. 58-61) are arranged much as in S. margi- 

 natus. It differs remarkably, however, in the raised posterior 

 margin of the segments, giving a serrate outline to the bodj'', 

 while the body tapers more rapidly towards each end than 

 any recent form known to us. In this respect it seems to 

 combine the characters of the present family and that of 

 Spirostrephon, a genus in many respects intermediate between 

 the Polyclesmidce and the Siphonantia, or sucking Myri- 

 opods. Four spiracles are represented on the tenth to the 

 thirteenth segments from the head. 



The genus Spirostrephon is in many respects intermediate 

 between this and the succeeding family. The head is free, as 

 in Polydesmus, but the sterna are soft, as in the Siphonantia. 

 S. Copei Pack., was found by Mr. C. Cooke in Mammoth Cave. 



Siphonantia Brandt. In the sucking Myriopods {Sugantia 

 of Brandt) we meet with the lowest, most vegetative, worm- 

 like forms of the order. According to "Wood the head is very 

 small and concealed beneath the prothoracic ring. The parts 

 of the mouth are fused and united into a sucking tube for the' 

 imbibition of fluids. The ej^es are either present or absent, 

 and the scuta, or tergites, may be prolonged laterally into 

 laminae which afford protection only to the back and flanks, 

 the central part of the abdomen being soft. The feet are 

 small and hidden beneath the broad bodj'^, Avhile the male ap- 

 pendages are placed on the seventh segment. 



In the genus Octoglena the e3'es are eight in number, 

 arranged in two converging rows. 0. bivirgata Wood is 

 brown, with a reddish stripe on each side, with about forty- 

 five segments to the bod}-. 



In Brachycyhe the rostrum is acute, much shorter than the 

 antennse, while the body is broad and flattened. The male 

 appendages, or clasping organs, are, as shown in Dr. AYood's 

 figures, simpl}^ modified feet adapted for clasping purposes, 

 as they are in Polydesmus, and are, therefore, not homologous 

 with the male appendages of insects, which are differently de- 

 veloped and grow out from a different portion of the segment. 

 The Brachyojbe Lecontei of Wood is from Georgia, and has 

 long lateral expansions to the tergites. 



