241] PROTEOCEPHALIDAE—LA RUE 241 



new material is desirable in order that a more complete knowledge of 

 this form may be had. 



This is one of the largest of the species of Ophiotaenia. The ob- 

 served length is about 40 cm. Schwarz (1908:26) thought that perhaps 

 the length might exceed that of 0. calmettci (35-80 cm.). The maxi- 

 mum breadth observed was 1.2-2.0 mm. The scolex is large, round and 

 muscular. It has a breadth of 1.5-2.0 mm. Barrois described an un- 

 armed rostellum. Schwarz found no rostellum, nor does his delineation 

 of the head, which is reproduced (Fig. 37), show such a structure. The 

 scolex is clearly set off from the neck. The four suckers are muscular, 

 prominent and nearly circular. They measure 0.60-0.70 mm. No func- 

 tional fifth sucker is present. The neck was not described by Barrois 

 or by Schwarz. The strobilation is distinct, altho the strobila has no 

 indentations. Proglottids are strongly attached. The length of the 

 largest proglottids is about 5.5 mm. and the maxhnum breadth about 

 1.5-2.0 mm. The excretory system is made up of two pairs of lateral 

 vessels, a dorsal and a ventral. 



The genital aperture is marginal and it alternates irregularly. It 

 is situated about the middle of the proglottid. The testes (Fig. 199) 

 lie in two well marked lateral fields between the vitellaria and the 

 uterus. Barrois gives 230-240 as their number, Schwarz 150-200. They 

 measure 0.060-0.070 mm. Of the cirrus-sheath and vas deferens 

 Schwarz says "the relation of the cirrus-sheath and vas deferens is 

 especially characteristic for this form. In ripe segments the greater 

 part of the cirrus-sheath is completely evaginated. There seems to 

 exist a special muscular apparatus which withdraws the cirrus-sheath, 

 when completely sexually mature, from the proglottid, so that it pro- 

 jects free from the margin. In young segments it lies in its normal 

 position within the segment". 



Schwarz has evidently misinterpreted the appearance in this case. 

 His own drawings show no evagination of the cirrus-pouch but a com- 

 plete evagination of the cirrus which is thick at the base, and filiform 

 at the tip. From this heavy base the ductus ejaculatorius runs straight 

 through the now greatly shrunken cirrus-pouch. There are some coils 

 of the ductus ejaculatorius within the basal part of the cirrus itself. 

 The writer has observed this condition in O. t rimer esuri. Schwarz 

 states that the cirrus is about 1 mm. long in O. marenzelleri. In his 

 drawing the cirrus-pouch extends about y 3 across the proglottid breadth. 

 The vas deferens forms a mass of coils before entering the cirrus-pouch. 



The vagina opens usually posterior to the cirrus-sheath. Its course 

 to the middle of the proglottid forms an arc. At the middle of the 

 proglottid it bends sharply posteriad and then its course is direct to 



