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 

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

 like fibres are continuous witli the bundles composing the 

 transverse bands on the genital somites. There can be little 

 doubt that they must be associated with the habits of 

 climbing vertical surfaces. The additional internal trans- 

 verse bands of muscles in the genital somites are absent. 



Septa G/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 (PI. XV. fig. SZ*). 



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

 ^ng more than three segments, and the muscle-ljands 

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

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

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

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

 typhlosole. 



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

 phiced 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 oft' from 

 tlie 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 i)lace 

 of origin and becomes attached to the anterior wall of 

 septum 9,10. All the vesicles lie close together dors:illy 

 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 se|)tum 

 8/9 is not back ward ly deflected ; the testis-somites are neai ly 

 1^ times larger than those in front or behind. In seciional 

 preparations (PL XVIII. fig. 10 c) the spermatocytes are s.-en 

 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- 



