344 PROCEEDINGS OF THE ACADEMY OF [1895. 



The dorsal pores begin on somite VII, and are placed in each 

 succeeding somite one-third of its length from the anterior end. 



The larger peritoneal corpuscles are elliptical, with a few small 

 oil drops of very regular size confined to a single circle close to the 

 periphery. 



F. parva is opaline white in color, and the prostomjum is conspicu- 

 ously roughened with rounded glandular nodules. 



This species is rather common between fallen leaves in damp spots 

 in the woods. July. 



Fridericia alba u. s. 



Length, 15-22 mm. Number of somites, 56-58. 



Setae usually four per bundle, with the exception of two or three 

 terminal somites, which have two. In certain of the ante-clitellar 

 somites five, six, or even seven, seta? are sometimes present. The 

 setae of the inner pair in a bundle of four are about three-fourths, or 

 over, the length of the outer. All setae are rather long and slender. 



The spermatheca? (Plate XIII, fig. 11) are almost exactly like 

 those of the last species, the sac being simple, but rather more 

 spherical, the stalk about four to five times its length, and without 

 glands at its mouth. 



The salivary glands (Plate XIII, fig. 8) are very slightly branched, 

 with only two or three branches, and may possibly be sometimes simple. 



The dorsal vessel arises in the twenty-second somite. The brain is 

 nearly oblong and slightly emargiuate behind. Dorsal pores begin 

 on somite VI. 



The nephridia have uot been studied. 



This is the most nearly aquatic of the four species, being found 

 most plentifully in the wet moss and leaves along streams in the 

 woods. Common at all seasons and the most generally distributed 

 species. 



The four species above described are easily distinguished from one 

 another by the characters of the spermatheca and salivary gland 

 alone, as follows: 



alba longa 



parva Spermatheca Salivary gland i 



simple simple 



agricola Salivary gland Spermatheca 



branched with diverticula. 



