NEW MAMMALIAN TAPEWORMS. 997 



The scolex (text-fig. 205) is of moderate dimensions, not very- 

 minute, and quite visible as such by the naked eye. It is 

 more or less spherical, and is marked by some black pigment 

 below the level of the suckers. A pigmentation of the 

 Slickers is not uncommon a.mong the Cestoidea, and it seems 

 occasionally to pervade the scolex also. The suckers have a 

 circular orifice, and present no marked features on examination 

 with a lens. They lie some way below the summit of the scolex, 

 aiid are directed laterally ; there is no trace, that I could see, of 

 an upward direction. The smoothly rounded upper end of the 

 scolex shows no hooks. The suckers lie near to the lower end of 

 the head, whicli is followed by a distinct neck of 2 or 3 mm. in 

 length, in which the strobilisation was not apparent. The 

 strobila are at first much broader than long, and each overlaps 

 its successor at the edges. In the larger specimen, the dimensions 

 of which are given above, the proglottids did not attain to an 

 equality in length and breadth until about three inches or so 

 from the scolex. They never attain to a length which is greatly 

 in excess of their breadth, as will be apparent from the measure- 

 ments which 1 have given above. It is noteworthy that in the 

 svTialler of the two individuals which are described here, the very 

 few last segments alone showed a length equal to their breadth. 

 In this worm (text-fig. 204) the last proglottid had an oval form, 

 and was of less diameter than those which immediately preceded 

 it. This form is usual for the last proglottid, and serves to 

 emphasize the fact that this specimen was complete and had 

 not begun to cast ofi" proglottids. The ripe proglottids differed 

 from the anterior ones in their greater thickness, and in the fact 

 that their surface was marked by a longitudinal furrowing, 

 caused as I should imagine by unequal distention with embryos. 

 The shape of these proglottids also was different from that of 

 those lying in front, in that they were hourglass-shaped, with, 

 however, as has already been mentioned, a greater diameter 

 posteriorly than anteriorly. The genital pores are unilateral 

 without exception from end to end of the body. They are not at 

 all visible until the segments have begun to increase in length, 

 and are perha,ps less obvious upon the very distended posterior 

 proglottids. The pores are particularly obvious in this species, 

 on account of the fact that they are borne upon slender processes 

 of the Body- wall, as will be more specially described later in 

 connection with the generative organs. These genital pjrocesses 

 lie near to the anterior border of the segments. 



If the above account of the external characters of this tape- 

 worm be compared with my account of the external characters of 

 Thysanotoinia gmnhiana, it will be seen that the two species, 

 though agreeing in many features, nevertheless show several 

 points of distinction, which enable them to be fully defined 

 as distinct species from these external chara.ctei-s only. It is 

 particularly to be noted that the individual of the two examples 

 of Thysanotcenia lemuris whicli I regfuxl as a not fully developed 



Piioc. ZooL. Soc— 1911,No. LXVIII. 68 



