296 WILLIAM A. HASWELL. 



reservoir (PL XXII, fig. 17, e.j\), which is always found to be 

 distended with spermatozoa. This is an elongated sac, much 

 dilated proximally, which runs almost transversely from near 

 the middle line of the body where the vasa deferentia open 

 into it towards the right, and opening into the base of the canal 

 of the penis. The latter organ (PI. XX, fig. 6, p.) is con- 

 tained, when retracted, in an elongated muscular sac lying 

 transversely with the mouth directed towards the left and 

 towards the dorsal side. It is a cylindrical, slightly curved, 

 chitinous body, having a wider proximal and narrower distal 

 end. In T. fasciata (PL XX, figs. 5 — 7) and T. quadri- 

 cornis (PL XX, fig. 8) the distal end is provided with a knob 

 or glans (gl.) ; in T. minor and T. novse-zelandiae, this is 

 merely represented by a slight rim (PL XXII, figs. 9 and 10). 

 The whole is enclosed in a sheath composed of circular and 

 longitudinal muscular fibres — the latter the stronger, and 

 enclosed by the former. At the opening of the penis the 

 sheath is continuous with the proper chitinous wall of the 

 organ, it is continuous also proximally with the sheath of the 

 spermatic reservoir and distally with the muscular investment 

 of the genital cloaca. In T. fasciata, where it turns back to 

 become continuous with the proper wall of the penal cylinder, 

 it is provided with a number of chitinous spines, which, when 

 the penis is retracted, lie in the interior of the terminal knob 

 or glans in a radiating manner, their outer ends, which are the 

 broader, embedded in the sheath and the acute inner ends 

 pointing into the narrow lumen. When the penis is pro- 

 tracted this inverted part of the sheath will become everted, 

 and the spine project on the exterior of the end of the penis, 

 thus enabling the organ to retain a firm hold during the act 

 of copulation. In T. minor and T. novee-zelandise there 

 is only a slight rim to effect this purpose; but in the latter 

 species (PL XXII, fig. 19) the female opening is provided with 

 inwardly directed spines, which doubtless effect the same 

 object. The interior of the penis and spermatic reservoir is 

 lined with a protoplasmic layer containing nuclei, but without 

 cell boundaries. Into the lumen of the ejaculatory duct there 



