202 Studies in Enehytraeid Worms 



a variety of organs, including the pharynx, tongue, oesophagus and 

 oesophageal glands, septal and salivary glands and intestine, in the 

 order in which they occur in longitudinal section. The mouth lies, 

 as usual, on the ventral side of the prostomium (Plate XXXII, mo.) 

 with the peristomium or first body segment as a lower lip. Behind 

 the intersegment 1/2 lies a taste organ (Plate XXXII, t.o.) or tongue. 

 It arises from the floor of the buccal cavity, and under certain conditions 

 has exactly the appearance of a valve. It projects into the pharynx, 

 and is capable of being moved forwards and backwards. The base of 

 the organ is broad, and the free end pointed. This gives it the outline 

 in longitudinal section of a short curved wedge. A pair of minute 

 processes (not shown in the illustration) may be seen laterally in the 

 posterior region. In view of the fact that the number and arrangement 

 of these organs vary with the species, and may be solitary, paired or 

 even quadrupled, their study is of considerable interest and importance. 



The pharynx is situated in the 3rd segment (Plate XXXII, ph.) and 

 has a strong dorsal infolding. It agrees in form and structure with that 

 of Enchytraeus pellucidus Friend, as described by Stirrup (7). There is 

 no trace of a stylet, neither can I find any evidence of a direct connection 

 between it and the septal glands. The muscles (Plate XXX,£>.m.) are very 

 strongly developed. Of the septal glands there are three pairs, winch, 

 by reason of their staining readily, are conspicuous objects in longi- 

 tudinal sections. They each consist of two or three unequal lobes 

 (Plate XXX, s.g.), the largest of which is dorsally placed, and posterior 

 to the smaller. Their form and appearance may be best judged by the 

 illustration. It will be well to observe that though the septa appear 

 to be wanting in the first four segments, those in 5/6, 6/7 and 7/8 are 

 strongly developed ventrally (Plate XXX, t.s.) in order to form a basis or 

 support for the glands, which project forward, and, like the nephridia, 

 each occupy portions of the two segments 4/5, 5/6 and 6/7. 



The next organs attached to the alimentary tract which arrest our 

 attention are .the peptonephridia or salivary glands. These are 

 developed, one on the dorsal, the other on the ventral surface of the 

 oesophagus (Plate XXXII, d.s.g. and v.s.g.). Some authors treat them as 

 part of the excretory system, but their use is still questionable, and we 

 therefore prefer to notice them here. They do not appear to open into 

 either the oesophagus or the pharynx, but are apparently blind appen- 

 dages to the former, extending from the 4th to the 7th segments. The 

 ventral salivary gland is closely attached to the under surface of the 

 oesophagus, and is possessed of a strong outgrowth in segment 4 which 



