375] ANOPLOCEPHALIDAZ—DOUTHITT 25 



The total length is 12.5 to 20 mm. The number of proglottids is 

 61 to 72. There is no neck. The first proglottid is about 40/i long, and 

 generally about five-sixths the diameter of the head. The strobila may 

 increase rapidly in width in the first few proglottids, or the fourth or 

 fifth may be four-fifths the diameter of the first. Mature proglottids 

 measure 1.5 mm. wide by 145/i. long. The maximum width of 2.5 to 5 

 mm. is reached about 7 mm. from the posterior end. Beyond this the 

 proglottids usually narrow rapidly and lengthen somewhat. The pos- 

 terior free border of each proglottid overlaps about half of the suc- 

 ceeding proglottid. 



The scolex is 625 to 750/u, broad near its anterior end. It narrows 

 distad, passing abruptly into the first proglottid. It is nearly square 

 in cross section with only slight indication of grooves between the 

 suckers. On the anterior end grooves occur between the suckers, fading 

 out just before the apex is reached. There is no indication of the 

 circular groove found in the last species. The very large suckers open 

 directly forward. Right and left suckers touch in the median line of 

 the scolex, and reach very nearly to the lateral cuticula (see Fig. 26). 

 The mouth is 70 to 90/x across. The muscular wall is 55 to 75/x thick. 



The genital anlagen appear in the first proglottid. The receptacu- 

 lum seminis fills in the 17th or 18th, and eggs are found in the uterus 

 in the 21st or 22nd. The genital pores are located midway on the 

 right margin and distinctly nearer the dorsal than the ventral surface. 

 The cirrus pouch extends first proximo-mediad and then bends directly 

 mediad, not enlarging beyond the bend. Its inner end lies well within 

 the excretory ducts. The passage of the cirrus is tortuous. In the 

 median end of the pouch is a portion of the vesicula seminalis which 

 later enlarges to fill the entire pouch. Outside the pouch is a second 

 portion of the vesicula. The testes shrink and apparently break down 

 very early. They are 50 to 60 in number and are 70/i long, being 

 usually somewhat longer than broad. Nearly all lie between the left 

 ventral excretory vessel and the vitelline gland, but not infrequently 

 a testis will lie wholly or in part laterad of the excretory vessel and 

 two or three may lie dorsad of the anterior part of the vitelline gland. 

 They extend entirely thru the medullary portion dorsoventrally. 



The vaginal pore is on the ventral surface of the cloaca. The 

 vagina lies ventrad to the cirrus pouch and partly behind it. Its walls 

 are highly glandular. The receptacular seminis is large and elongate, 

 reaching laterad to the ventral excretory vessel. A small part at the 

 lateral end is indistinctly constricted off from the median portion, 

 making it somewhat bilobed The oviduct arises just anterior to the 

 lower median corner of the vitelline gland and passes laterad and 



