176 Transactions. 



few segments was a third chaeta present in a bundle. The chaetae are 

 straight and of equal lengths. 



The clitellum covers segments xii and xiii, and about half xi. 

 The head pore lies between the prostomium and peristomium ; the 

 first dorsal pore occurs in segment vii. These dorsal pores, as Eisen has 

 pointed out in his account of some American species of the genus, do not 

 lie in the intersegmental furrows, but at a little distance from the anterior 

 septum of the segments, at about one-quarter the distance between the 

 two septa. 



The brain is convex posteriorly. 



The pharynx lies in segment iii, and has the usual bisym metrical, non- 

 ciliated pad of long columnar cells on its dorsal wall, through which the 

 ducts of the septal glands open. 



The oesophagus passes through the following segments as a straight 

 narrow tube lined with low ciliated cells, outside which is a rich vascular 



plexus. In segment xiv the gut enlarges, and this 

 enlarged region, which traverses segments xiv, xv, 

 and xvi, is constricted at the septa. In these seg- 

 ments the epithelial cells assume a very characteristic 

 form and arrangement, which has been utilized by 

 Eisen (7) as one of the diagnostic features of the 



„ „ , „ genus. The cells are very tall, and bear long cilia, 



Fig. 2.—F. bollonsu ° -, . ,, A , ' , , , 8 



and amongst them, as that author has shown in 



A coelomic corpuscle, a ser i es f beautiful drawings, are found other 



face tfroT'cira cells ' eacn of which is llollowed out by a canalicule 



outline). which at its base curves at right angles to the 



axis of the cell. These cells, which were studied 

 years ago by Michaelsen, who termed them " chylus cells," are not all of 

 the same height, so that the surface of the epithelium is very irregular. 



In segment xvii this region of the chylus cells passes into the ordinary 

 intestine, in the cavity of which dirt accumulates. The epithelium is lower, 

 the cells being only about one-quarter the height of those in the preceding 

 region, and the cilia shorter. There are here no chylus cells. 



The dorsal vessel becomes evident at about the 20th segment : in one 

 case I noted it in the 19th ; in another in the 21st. I did not attempt to 

 trace out the vascular system. 



Septal glands lie in segments iv, v, and vi. 



There is on each side a simple peptonephridium, lying below the 

 oesophagus in segments iii to vi ; at its hinder end it branches or rather 

 bifurcates, one branch being narrow and short. 



The nephridia have a large ante-septal region, consisting of the usual 

 mass of connective tissue traversed by a fine canal which winds about 

 therein. After passing through the septum it enters and traverses the 

 post-septal region, which is distinctly less in extent than the ante-septal. 

 It is difficult to trace out the details or to reconstruct the outlines from 

 the study of sections, but in the series of transverse sections I counted 

 13 sections through the ante-septal and 9 sections through the post-septal 

 regions respectively. The duct leaves the latter near its commencement, 

 close behind the septum. 



The Genital Apparatus. — The testes are lobulated. The sperm-funnel 

 has the usual massive form ; it is apparently somewhat p3^riform in shape, 

 though it is abruptly bent on itself, and it appears to be rather broader 

 than long, unless it has shrunk unequally. This region is made up of 



