some new Species of Drawida. 517 



a distinct annular rim. The disc is composed of circularly 

 arranged muscle- fibres, while, at any rate, some of them 

 belonu- to the transverse series, for a few of these sphincter- 

 like fibres are continuous with the buudles composing the 

 trausverse bands on the genital somites. There can be little 

 doubt that they must be associated with the habits of 

 climbing vertical suifaces. The additional internal trans- 

 verse bands of muscles in the genital somites are absent. 



Septa 6/7, 8/9 are very thick, chiefly the last two ; septum 

 9/10 only slightly so, while the succeeding ones are very 

 tender. Septa 8/9 and 9/10 may be dislocated, backward and 

 forward respectively by a somite's length (PL XV. fig. 3i). 



Alimentary Canal. — Pharynx is large and muscular, occu- 

 pying more than three segments, and the muscle-bands 

 have the usual thickened appearance of septa. ffiso|)hagus 

 simple, slender, extending up to somite 10. Gizzards three, 

 fairly large, occupying somites 10-lG or 11-16. No dorsal 

 eriteric appendages, or only a few are present. There is no 

 typhlosole. 



Circulatory System. — There are five hearts, the last being 

 placed in segment 10. A lateral longitudinal vessel is 

 present, extending up to somite 22, connected to the dorsal 

 vessel by secondary cornmisures which are given ott' from 

 the hearts near their point of origin. The vessels are 

 mainly composed of connective tissue, the muscle-fibres 

 being confined practically to the hearts. 



Genital System. — The male organs comprise two pairs 

 of testis-sacs, suspended by septum 9/10 on its anterior and 

 posterior faces, those of one side right or left in a state 

 of fusion. The septum 8/9 is usually very thick and 

 generally, though not as a rule, dislocated backwards, and 

 the seminal vesicle belonging to this septum leaves its place 

 of origin and becomes attached to the anterior wall of 

 S'Cptum 9/10. All the vesicles lie close together dorsal iy 

 over the oesophagus, or may lie separated below this 

 structure. The combined, yet distinctly bilobed, seminal 

 vesicles are restricted to their own somites, if the septum 

 8/9 is not backwardly deflected ; the testis-somites are ncai ly 

 li times larger than those in front or behind. In seclicjnal 

 preparations (PI. XVIII. fig. 10 c) the spermatocytes are Sv_eu 

 to occupy respectively the anterior inner border of their 

 vesicles, the seminal funnel being in intimate contact with 

 the testes. The other contents of the vesicles are sperms 

 and trophocytes in various stages of development. The 

 mesenterial wall forms a dense membrane, and is further 

 supported by the presence of muscle-fibres, mostly irregu- 



