Benham. — On New Species of Earthworms. 289 



last heart is in segment 13 ; it and the heart in 12 are 

 "enteric," while in 10 and 11 are " lateral hearts." 



The Alimentary System. — The gizzard is large, occupies 

 segments 6 and 7, the septum 6/7 being attached round its 

 middle. The oesophagus bears a dilatation in segment 15, 

 which is not constricted from the main tube. The gut then 

 narrows, but in the 18th commences to increase in diameter 

 till it has reached its full diameter in the 23rd segment. 



The worm is micronephric. 



Reproductive System. — The testes and ovaries are situated 

 on the hinder wall of their segments, in each case underneath 

 the funnel of the duct, as in OctochcBtus multipores and other 

 species. There are four sperm-sacs. The spermiducal glands 

 are closely zig-zag, confined to their segments. 



There are no peuial chsetae, but transverse muscles are 

 present in these segments. 



The spermathecae are provided with a single lobulated 

 spherical diverticulum. 



EXPLANATION OP PLATES XXII.-XXVI. 

 Plates XXII.-XXV. 



The illustrations of the anatomy of the earthworms described in 

 this paper are purely diagrammatic, indicating only the segmental posi- 

 tion of the various organs, the worm being supposed to be slit up along 

 the dorsal line and the body-wall pinned aside. 



A group of three diagrams refer to each worm herein described. The 

 left-hand diagram in each of the groups referring to a species represents 

 the external features. The location of the various genital pores is repre- 

 sented as round black dots (if on a papilla this is left white), the clitellum 

 is obliquely shaded, the tubercula pubertatis are vertically shaded. 



In addition, the arrangement of the chaatse — labelled a, b, c, d — is in- 

 dicated in two or more segments in each case, usually in the 5th and the 

 22nd ; they are omitted in the remaining segments for clearness' sake. 

 The true relative spacing of the chsetae is shown, except where they are 

 very numerous. 



The position of the nephridiopores is indicated by the small circles on 

 one side of the figure. 



The middle figure represents the alimentary canal and so much of 

 the vascular system as is diagnostic. The latter is black. The gizzard is 

 indicated by vertical shading, the oesophageal glands by more or less 

 horizontal lines. The intestine is not represented as being constricted, 

 which is, however, the case in most worms. 



The right-hand figure shows the reproductive system. The gonads 

 are in black. The sperm-sacs are dotted. The sac with penial chsetae 

 when present is indicated, and the muscular duct of the spermiducal gland 

 is transversely striped. The transverse muscles in the 18th segment are 

 shown. 



No attempt is made to give the relative sizes of the worms or of the 

 various organs. Nor has it been considered necessary to label the various 

 organs, since to any one who is familiar with the anatomy of any earth- 

 worm the structures here indicated will be sufficiently intelligible. 

 19 



