Hi THE MYRIAPODA OF NORTH AMERICA. 



anterior portion of the labium, which I have frequently seen separated by a suture, being 

 composed of the episterna and primitive sterna of the same subsegment. The mandibles 

 are probably the appendages of the third basilar subsegment, the posterior portion of the 

 labium being composed of the sterna of the same subsegment. Two plates, which are 

 bent round the sides of the posterior portion of the labium, may be the episterna. 

 The sternal portions of the fourth basilar subsegment are similar to those of the segments 

 of the body. Among the Lithobiidae the structure of the under portion of the head is 

 almost identical with that described above. 



Among the Geophilida? the parts of the mouth are so consolidated and confused that it 

 is impossible to recognize in the adult the original plan of construction and development. 

 On examining the under surface of the head of a Mecistocephalus, we will find the labium 

 very large, as are also the mandibles, while the maxillae are apparently wanting, but the 

 maxillary palpi are recognizable. Among the Cermatiidae the labium is moderate, cleft in 

 the middle, the two lateral halves being movable on one another, so as to form as it were 

 an additional joint to the mandibles ; which are otherwise enormously developed, espe- 

 cially as to length. The palpi are very long. The maxillae and maxillary palpi are well 

 developed. 



Sub Ord. SCHIZOTARSIA.* 

 AntennjE longissiruai, setacete, cum tarsis inultiarticulatfe. Oculi compositi. 

 Antennas very long, setaceous, together with the tarsi multiarticular. Eyes compound. 



Fam. I. CERMATIIDAE, Leach. 



• Scuta 8. Segmenta 16. Sterna 1G. Scutorum stomata mediana. Pedes antennaequc uiultiartieulatae. 

 Scuta 8. Segments 1(3. Stomata of the scuta median. Feet and antenna multiartieulate. 



In the Cermatiidae the head is large, more or less truncate anteriorly, having its surface 

 rough and uneven. The 1 eyes arc compound and very prominent. The palpi very elon- 

 gate and spinous. The antennae very long, and composed of a multitude of joints. The 

 mandibles are elongate and distant. The scuta (eight in number) are rounded and deeply 

 emarginate posteriorly, where they are furnished with a longitudinal, slit-like orifice or 

 stoma. Their surface is more or less roughened with minute tubercles or spines. Their 

 border is everted, and generallj crenulate and spinous. The legs are very long, and ser- 

 rated 1>\ parallel rows of spinulae. They are also furnished with rings, of long slender 



1 Brandt, Recueil, p. 26. 



