DESCRIPTIONS OF GENERA AND SPECIES 



671 



The colour of the living worm is a bright green dorsally, changing into a pinkish 

 yellow ventrally. The prostomium is not large and is not imbedded in the first 

 segment ; the segments are much annulated ; the following are the numbers of the 

 annuli given by Benham, and illustrated in a figure (fig. i). 



Somites i and ii contain together 3 annuli. 



iii » .. 7 „ 



iv M „ 6 „ 



^ » JJ 7 I! 



vi „ „ 6 



vii ,, „ 6 



viii „ „ 6 



1^ J! II 4 II 



^ =. .. 3 



And there are three annuli in succeeding; segments. 



The extent of the cliteUum is a little doubtful. I gave segments x-xxx ; Benhamt, 

 segments xiii-xxv ; but both these should be placed one segment further back, as 

 apparently both Benham and I at first missed the first segment of the body, which 

 is fused with the second; On the anterior segments the setae are longer and thinner 

 than elsewhere and have a spear-shaped extremity ; the first segment of the bodyi 

 which is fused with the second, has no setae at all. The sperm-ducts open externally 

 on to segment xx. 



There are five specially-thickened septa ; the first of these lies between segments 

 iv/v. The gizzard is in segment vii. In the tenth segment is a pair of calciferous 

 glands which looks like a swelling upon the oesophagus; it is very vascular. 

 The existence of carbonate of lime in the gland has been proved hj Benham. 

 The intestine commences at about the fourteenth segment and has a typhlosole. The 

 dorsal vessel is double in the anterior region of the body; this duplication begins 

 in the fifth and ends in the ninth segment. The two halves of which the dorsal 

 vessel is in these segments composed does not remain entirely separate ; at the septa 

 they unite together to separate again later. In the ninth segment the two halves 

 of the dorsal vessel are extremely wide as compared with what they are in other 

 segments ; this state of affairs is very suggestive, as I have already noted, of the 

 commencement of the formation of a heart. In segments v-xi are commissural vessels 

 putting the dorsal and the ventral longitudinal vessels into communication; those of 

 the last four of these segments are larger than the rest and have a moniliform 

 appearance, indicated by Benham. The nephridia commence in the third segment; 

 the first twenty pairs (about) have a large caecum attached to the muscular duct 



