46 BULLETIN 69, UNITED STATES NATIONAL MUSEUM. 



The yolk gland (figs. 33, 35, 36, yg.) is spherical, 45 to 60/* in 

 diameter, located in the median line near the ventral surface of the 

 segment, behind the middle of the ovary, in the niche between the 

 right and left lateral lobes. 



The uterus Avas not yet developed in the specimens studied. 



Remarks. 



In certain respects the tapeworm described alcove is strikingly simi- 

 lar to a form from Fulica atra described by Jacobi (1898c, pp. 95-104, 

 pi. 6, figs. 1-16) as Tcenia inflata Rudolphi. 



The chief characters of this form, summarized from Jacobi's de- 

 scription, are as follows: 



Length 80 to 100 mm., width 2 to 3 mm. Head with a prominent 

 rostellum [similar in shape to that of Diorchis «cv^;?^^;i« to], armed with 

 a crown of 10 hooks, 23/* long [similar in form to those of Diorchis 

 acuminata]. Segments broader than long throughout the strobila. 

 Genital pores unilateral. Longitudinal muscles arranged in two 

 layers of bundles, an outer layer of numerous small bundles close to 

 the surface of the body, and an inner layer of 8 larger bundles [as in 

 Diorchis acuminata']. The cirrus pouch and vagina pass on the dor- 

 sal side of the longitudinal nerve and excretory vessels. Testicles 

 two. Seminal vesicle absent ; vas deferens enlarged within the cirrus 

 pouch to form a seminal reservoir. Cirrus pouch with an outer layer 

 of longitudinal muscles [as in Diorchis acuminata]. Size of cirrus 

 pouch " not exactly stated, but it does not extend as far as the median 

 line. Cirrus unarmed ; when extruded has a bulbous enlargement at 

 the base [as in Diorchis acuminata], and, to judge from the scale of 

 magnification to which Jacobi's figures are drawn, measures from 6 to 

 8/* in diameter, the bulbous enlargement being 12 to 14/x in diameter. 

 Vagina enlarged to form a seminal receptacle. Ovary trilobecl ; shell 

 gland spherical, ventral of and posterior of the ovary. The ovary, 

 when fully mature, is about one-fourth as wide as the segment. The 

 uterus is a simple sac, which develops on the dorsal side of the ovary 

 and ventral of the testicles. Eggs with two thin shells in addition 

 to a membrane, which closely invests the oncosphere. The shells 

 are drawn out into pointed processes at the poles. Oncosphere 17/x 

 in maximum diameter, outer shell 37 to 41/j, in length, hooks of onco- 

 sjDhere 9.2/* long. 



'^ Clerc (1903) describes and figures the cirrus pouch in a form from Fulica 

 atra which he has identified with Jacobi's species, as very long and extending 

 , far beyond the median line. Jacobi, although remarking that the cirrus pouch 

 is very long, distinctly states that it extends almost to the median line, and it is 

 thus shown in his figures. Whether such a wide variation in the size of cirrus 

 pouch may occur, or whether Clerc had before him some other species, are ques- 

 tions which can not be definitely determined until further evidence is available. 



