UiiO Mil. li. A. BAiLIS AND LT.-COL. CLAYTON LANE ON 



direction of whose points is away from the cloacal opening. 

 Tliere exists, however, a bakl Y-shaped area whose narrow stem 

 reaches from the tip of the tail to the anus and whose broad 

 arms stretch thence laterally and anterioi'ly as far as the most 

 anterior of the lateral j)f>pillee. 



The short I'ight spicule (PI. YIII. fig 34) is wide at the base 

 a.nd narrows somewhat abruptly about its middle, continuing 

 narrow thence to its rounded point. The long left spicule has 

 the same general shape as the right except that the shaft narrows 

 at about the junction of the antei-ior and middle thirds, and that 

 the middle third has at least the appearance of being the nairowest 

 part. When the large spicule is extruded it is seen that it is 

 hollow-looking, faintly sti-iated, with a fine colourless outer layer 

 which thickens to form the extreme point of a slight terminal 

 expansion (PI. VIII. fig. 35). 



In the female, the vulva, shaped as a slight tranverse slit, opens 

 into a vagina with a general anterior direction. In the specimen 

 examined its first 2 mm. was strongly muscular and narrow, the 

 beginning being markedly tortuous ; the next 0"5 mm. was dilated 

 and full of eggs ; then followed a narrow muscular loop running 

 posteriorly and dorsally nearly to the level of the vulva and 

 returning on itself to enter another short dilatation close to the 

 first one ; thence it ran forward as a narrow muscular tube taking 

 a nearly straight course to the jDOstei'ioi- end of the oesophagus. 

 Immediately after turning posteriorly at this point it was found 

 broken and the continuation could not be discovered. The coui^se 

 traced measured 11'5 mm. Owen's (1836, p. 126) account of his 

 dissection gives it a course of over 25 mm. before dividing into 

 the two uteri. The tail of the female is, in a lateral view 

 (PL VITI. fig. 37), rounded dorsally and flattened ventrally, 

 while in a ventral view (PI. VIIT. fig. 36) its end is bluntly 

 rounded and carries close to the tip a. paii- of unusually massive 

 caudal papillae. It is clear that a collapse of the cuticle about 

 these papillfe might readily produce the "three-lobed" appearance 

 which Levinsen (1889) figui'es {vide iv/ra, p. 297). 



The ovum has a thin colourless shell with a very fine granu- 

 lation on its outer surface and the usual polar cap. In the 

 female examined the ova contained fully-formed embryos, some 

 of which were found in the act of escaping through the thinned 

 pole (PI. YIII. fig. 38). 



The justification for the correctness of the list of sj'nonyms 

 given above is to be sought in the following lines and in 

 Table YIL, page 302. 



The original description of Gncdlwstoma spinigerum (Owen, 

 1836) based on specimens removed from tumours in the stomach- 

 wall of a young tiger which died in the London Zoological 

 Gardens, corresponds, so far as details are given, with that just 

 written a,bove, except that he described the armature of the head- 

 bulb as similar to that of the body and noted only one spicule and 

 four pairs of papillae, apparently three of the large lateral ones 



