TYPES OF SPECIES OF CESTOIM — KREFFT. 27 



The cirrus when fully everted is seen to be a relatively large 

 organ of about 05 mm. long, with a breadth of 0.16 nun. at its 

 base and tapering slightly towards the extremity. It is beset 

 with a great number of very powerful hooks set spirally and as 

 closely as their enlarged bases allow. Each hook has the form 

 shown in PL iv., fig. 4, the base being about 0-0145 mm. long. The 

 total length of hook is 022 mm. Tlie length of the structure 

 is somewhat less than that of the cirrus hooks in Acoleus armatus. 

 Besides, the shape is seen on comparison with Fuhrmann's tigure 

 to be different, being intermediate between the latter and that of 

 Acoleus crassus, Fuhrm. 61 The base is sunk into the cirrus 

 wall, oidy the claw remaining projecting. 



The female genitalia are characteristic in that there is neither 

 a female aperture nor a vagina. The ovary is a rather broad 

 organ (08 - 0'92 mm.) lying in the middle of the segment and 

 possessing the general form of an arch, the cavity of which faces 

 postero-dorsally. The gland consists of a large number of small 

 tubes which are not readily separable into two groups or wings. 

 In section it is seen that the organ is really bilobed, the middle 

 piece or bridge being rather wide when compared with the size 

 of the ovarian tubes. The bridge is situated quite ventrally, 

 1\ ing immediately above the inmost layer of transverse muscle 

 fibres, the tubes being given oft in an antero-dorsal direction. 

 The short oviduct travels posteriorly and slightly dorsally from 

 the middle of the organ. The vitelline gland is a large solid 

 organ of an elongate kidney shape, being about - 40 mm. broad. 

 Its cavity faces forwards and slightly dorsally, the whole organ 

 lying at the same dorso-ventral level as the ovary, the shell gland 

 lying at a more dorsal level than either. The posterior border 

 of the vitellarium is slightly lobed. The vitello-duct is very 

 short, passing forwards and upwards to the shell gland, which is 

 a small rounded organ lying just antero-dorsally to the yolk gland. 

 Situated in the transverse plane between the ovary and the 

 vitelline gland, is a long thin receptaculum seminis, the outer 

 ends of which may be more swollen than the remaining parts. 

 This structure is connected at its middle with the oviduct just 

 in front of the shell gland. In regard to the closely allied 

 Acoleus armatus, Fuhrm. (=A. vaginalis (Rud.), Fuhrmann) 62 

 states that the powerful cirrus seems to be able to penetrate 

 some part of the parenchyma to liberate spermatozoa which 



S1 Fuhrmann— Centr. Bakt., I., xxviii., 1900, p. 370-1. 

 62 Fuhrmann— Centr. Bakt., I., xxvi., 1899, p. 621. 



