78 IJni'iCrsily of Micliitj'in 



much less strongly so than in, c. g., Ariomis ulophilus; keel 

 longer than median region of metatergite, its anterior lobe 

 large and rounded. (PI. 30, Fig, 210.) In the third and 

 fourth metatergites the keels are not longer than the middle 

 region ; anterior lobes smaller ; anterior margin incised each 

 side of a distinct lobe. (PI. 30, Figs. 210, 211.) Keels of 

 other segments shorter than median region of metatergite. On 

 the keels of the fifth and succeeding segments the anterior 

 lobe becomes smaller and is bent upward, soon appearing 

 merely as a tubercle, while the lobe of the caudal margin 

 remains distinct and is usually distally obtusely angular. The 

 lateral lobes of keels, especially the anterior ones, also tend 

 to be bent more or less upward. The porigerous lobe is typic- 

 ally bifid at the tip, the pore opening between the two sub- 

 divisions a little above the edge, not elevated on a secondary 

 cone or eminence. The caudal border of segments divided into 

 lobes by longitudinal furrows and corresponding crenations as 

 in Arionus, the crenations becoming deeper on the more caudal 

 segments. Dorsal surface of segments densely coarsely gran- 

 ular, two granules in each of jfoin- longitudinal rows on each 

 metatergite a little larger, more tubercle-like than the others, 

 these tubercles more distinct on posterior segments. (See also 

 PI. 29, Fig. 207.) Keels of seventeenth to nineteenth seg- 

 ments four-lobed and having posterior angles produced, the 

 processes on nineteenth segment obviously larger than the 

 caudal teeth or crenations of the median region /of segment. 

 (See PI. 29, Fig. 207.) 



Cauda in general outline posteriorly rounded, but with a 

 short distal piece set ofT and truncate across end; across basal 

 region a transverse series of four tubercles, the end one on 

 each side projecting as a distinct lateral process or tooth; sur- 

 face in front of these tubercles with smaller granules. (PI. 



