^KT. 7 CESTODE PARASITES OF BIRDS ^LINTON 27 



HYMENOLEPIS ANCEPS, new species 



Figures 71-78 



Scolex. — Bluntly rounded or pyramidal, suckers directed forward ; 

 rostellum not seen exserted, but evidently short; hooks in a single 

 circle, about 18, length about 0.012 mm., strongly recurved, dorsal 

 root short, ventral root about as long as the recurved blade. 



Strobile. — Segments begin a short distance back of the scolex, at 

 first much crowded, breadth many times the length, increasing in 

 length and breadth gradually, but remaining much broader than 

 long. There are two types of strobiles. In one the anterior seg- 

 ments are exceedingly short, with rounded margins, imparting a 

 finely crenulated margin to the strobile, breadth much greater than 

 the length; for example, breadth 0.28 mm., length 0.014 (fig. 74). 

 In the other type the segments soon become well defined with the 

 breadth of the posterior end greater than the anterior, giving a 

 sharply serrate lateral margin to the strobile; for example, breadth 

 0.21 mm., length 0.028 (fig. 73) ; maximum breadth about 3 mm. 

 Genital pores unilateral, about middle of margin, or a little in 

 front of middle; cirrus short, unarmed; cirrus-pouch long oval- 

 elliptical, with rather thin wall. In an adult, unripe proglottis 0.24 

 mm. in length and 1.92 in breadth the cirrus-pouch measured 0.28 in 

 length and 0.056 in diameter. The inner two-thirds, or more, of the 

 cirrus-pouch functions as a seminal vesicle. The folds of the vas 

 deferens at the base of the cirrus-pouch are voluminous but were 

 not seen to expand into an inner seminal vesicle. Testes three, 

 lobed, two of them close together on the antiporal side of the median 

 line, one on the poral side (fig. 75), The vagina opens on the 

 ventral side of the cirrus; at first a slender tube lying on the ventral 

 side of the cirrus-pouch, it expands into a large seminal receptacle 

 which persists after the uterus has developed (fig. 76). The ovary 

 is small, lobed, situated on the median line. The vitelline gland is 

 compact, three-lobed. when fully developed, on the median line 

 dorsal to the ovary. The uterus is irregularly lobed and extends 

 from maririn to margin in the ripe proglottides (fig. 76). The 

 dorsal and ventral vessels of each pair of lateral excretory vessels 

 lie near together, the ventral being much larger than the dorsal, 

 and the cirrus and vagina pass dorsad of the poral pair. The longi- 

 tudinal mus'les are strongly developed, and lie in two circles, an 

 outer continuous and an inner discontinuous layer (fig. 77). 



The following measurements were made of specimens mounted in 

 balsam : Breadth of scolex from 0.13 to 0.16 mm. ; diameter of suckers 

 0.075; length of hooks about 0.012. No complete strobile was 

 mounted. In one measuring 54 mm. the length of the posterior 

 proglottis was 0.24, the breadth 1.92. 



