1901.] AND AEEANGEMEKT OF EARTHWORMS, 199 



seventh and the eighth segment, inasmuch as no recognizable 

 septum divides those segments from each other. 



The oesopliagus extends back as far as the xvth segment, in 

 which segment the intestine commences. The calciferous glands, 

 of which there may be said to be a single pair in this as in other 

 species of TypJweus, do not present the appearance of discrete 

 pouches opening into the gut ; they form an oval reddish-coloured 

 swelling situated in segment xii. The mtestine has a typhlosole ; 

 but this is not apparent until segment xxx. (about). The charac- 

 teristic intestinal glands of the genus are visible far back upon the 

 intestine, commencing with segment Ixxsiv. or thereabouts. They 

 occupy in all five segments, and those of successive segments are 

 separated by the septa. The dorsal vessel lies between the glands 

 of the right and those of the left side. 



Intersegmental septa. — A number of septa lying in front of and 

 behind the gizzard are thickened. In front of the gizzard are two 

 such septa; behind the gizzard are three thickened septa. The 

 space occupied by the gizzard — the whole of the space formed by 

 the coelom of segments vii. and viii. — appears to be entirely un- 

 divided by any septum or even traces of that partition. 



Vascidar system. — The only point to which I direct attention in 

 the structure of the vascular system is the number and the position 

 of the " hearts." Of these there are six pairs, of which the first 

 lie in the viiith and the last in the xiiith segment. 



Nephridia. — These organs consist, as in the other species of the 

 genus, of numerous micronephridia. 



Reproductive organs. — The male gonads and their duct and the 

 sperm-sacs are in this, as in other species of the genus, limited in 

 number to a single pair. The testes and funnels lie in the xith 

 segment, and the following one, whose capacity is thereby extended, 

 contains the sperm-sacs. The sperm-sacs are of considerable size, 

 measuring 6 mm. in extreme length ; they are flattened and broad, 

 and of a roughly triangular form, the apex of the triangle being 

 posterior in position, the margins are somewhat lobulate. The 

 spermiducal glands are each coiled into a tight mass, throughout 

 which, however, the tubular structure of the gland is perfectly 

 obvious. The muscular duct is of fair length, and its calibre is 

 barely one third of that of the thicker parts of the gland-tube. 

 Between the opening of the two glands the ganglionic swelling 

 upon the nerve-cord is considerably larger than the corresponding 

 swellings in other segments. 



The penial setae are rather longer than those of T. incommodus, 

 of which a drawing is exhibited (text-fig. 57, p. 202), and they are 

 remarkable for being apparently of a very delicate structure at the 

 free end, which in all the setse that I have examined was much 

 bent and in different directions. The extremity is hardly sculp- 

 tured, a very fine pitting being all that is visible. 



The spermatliecce have a longish muscular duct, to the commence- 

 ment of which upon the outside is aifixed a somewhat fan-shaped 

 diverticulum. 



14* 



