THE MTRIAPODA OP NORTH AMERICA. 229 



resistant shell. The feet are hidden beneath the broad body. The male genitalia are 

 placed in the seventh segment. In the classification of the families and genera I have 

 followed Mr. Brandt,* his arrangement, as far as the two species I have seen enable me to 

 judge, being founded on natural characters. 



He adopts two families, which are characterized by the presence and absence of eyes. 

 Though this would of itself scarcely seem to be sufficient to separate groups of such 

 rank, yet, as it is associated with many differences in form tifcc, it serves as the most 

 tangible distinguishing mark. 



This suborder seems to stand at the bottom of the Myriapoda. In external appear- 

 ance and form it approaches most nearly to the Vermes, and has undoubtedly the lowest 

 structural development. 



Fam. POLYZONID.E. 

 " Oculi parvi, simplices, in media fronte inter antennes conspicui."f 

 Eyes small, simple, conspicuous in the middle of the anterior surface of the head between the antenna?. 



Mr. Brandt described this family under the name of Ommatophora, and the following 

 under the name of Typhlogena ; but I have adopted the names of Polyzonidse and Sipho- 

 nophorida? of Newport, for the reason that the former are not consistent with the laws of 

 modern scientific nomenclature. 



Genus OCTOGLENA.J 

 Oculi octo, in seriebus duabus simplicibus dispositi. (Fig. 59.) 

 Eyes eight, arranged in two simple series. 



The eyes in this genus are very prominent, and are arranged in two straight rows, which 

 are so placed, one on each side near the base of the antenna?, as to be convergent inferiorly. 



0. BIVIRGATA. 



0. brunnea, utrinque virga fusca ornata; segmentis fere 45. 



Brown, with a fuscous stripe on each side ; segments about 45. 

 O. bivir«ata, Wood, Proc. Acad. Nat. Sci., 1864, p. 186. 



* Recueil De Mem., p. 49. f Brandt, he. <!t. 



% Wood, Proc. Acad. Nat. Sci., 1861, p. 186. j-Xurj, oculus. 



