1899.] NATURAL SCIENCES OF PHILADELPHIA. 127 



injuries may be the result of previous freezing. Unstained sections 

 show that the pigment is in the form of minute granules deposited 

 thickly in the epidermal cells. These granules form a very densely 

 packed stratum toward the outer surface of the cells, but become 

 fewer and finally altogether absent toward their basal surface (fig. 

 8). Pigmentation is not confined to the outer surface of the body, 

 but affects as well all internal epithelia which have been derived 

 from ectodermal invaginations, as the setigerous glands, lining of 

 buccal cavity and pharynx, genital burs?e, stalk of the spei'mathecre, 

 terminal vesicles of the nephridia and the lateral portions of the 

 nerve cord. 



Except that it is deeply cleft in front where its angles pass into 

 the circumoesophageal connectives, the supra- oesophageal ganglion 

 is nearly quadrate; the posterior border is almost sti-aight. It is 

 situated in somites I and II (fig. 4 and fig. 7, eg.). The body 

 walls are unusually thin for an Enchytrseid, which results from 

 the weakness of the longitudinal musculature (fig. 8). The 

 dorsal blood vessel becomes free from the alimentary canal in the 

 clitellar somite (XII). It contains a usually inconspicuous car- 

 diac body composed of two or three rows of cells. 



No important pecuharities are apparent in the structure of the 

 alimentary canal. The pharyngeal pad (fig. 2), occupies the 

 second and third somites. It is preceded in the first somite by 

 a pair of lateral appendages which project into the lumen of the 

 buccal chamber. AVhen retracted it forms the cephalic wall of a 

 dorsal pouch, the posterior wall of which is the much-folded 

 pharyngeal wall. Otherwise the alimentary canal is simply saccu- 

 lated, and cihated throughout. The chlorogogue cells begin in IV. 

 They are very high and slender, the bodies very transparent, but 

 filled with pigment (?) granules and fat like globules. Large 

 septal glands are attached to the posterior faces of septa IV- V, 

 V-VI and VI-VII, and occupy the greater part of the succeeding 

 somites. There are no salivary glands (peptonephridia of Benham). 



Nephridia are situated in every somite posterior to VII. These 

 organs each consists of a long, narrow tube, very closely and intri- 

 cately folded ; but the loops do not communicate laterally with one 

 another to form a plexus. Throughout its course the lumen is 

 relatively large and the walls thin, so that the character of a tube 

 is not obscured, as in many Enchytraidse. The folded tube forms 



