ART. 20. TWO NEW INTESTINAL. TREMATODES TUBANGUI. 3 



only the points of disagreement between the Chinese and European 

 forms, but also the variations that occur in the European form 

 itself according to the descriptions of different writers. These need 

 not be discussed in detail, but on the whole they seem to indicate 

 the existence of varieties in the species. The Chinese variety is 

 shorter and comparatively wider than the European specimens 

 originally described; the prepharynx is longer, the acetabulum 

 larger and placed more posteriorly; the testes are transversely 

 elongated and very noticeably crenated around their margins. 



Description. — Length, 1.6 to 2.05 mm.; maximum width, 0.39 to 

 0.52 mm., measured in the neighborhood of the posterior testis. 

 Lateral margins of the body, from the collar to the acetabulum, 

 rolled ventrally, thus forming a shallow groove on the ventral sur- 

 face of this region of the body (fig. IB). Cuticle provided with 

 strong spines which become sparser posteriad and may disappear 

 entirely behind the posterior testis. 



Oral sucker, 0.081 to 0.114 mm. long, 0.11 to 0.13 mm. wide, ter- 

 minal, with the opening toward the ventral surface. Prepharynx 

 0.09 to 0.13 mm. long; pharynx 0.09 to 0.11 mm. long by 0.06 to 0.07 

 mm. wide; esophagus 0.17 to 0.31 mm. long, bifurcating in front of 

 the acetabulum into two simple intestinal branches which reach 

 nearly to the posterior extremity of the body. The acetabulum is 

 large, measuring 0.22 to 0.27 mm. long by 0.21 to 0.25 mm. wide, and 

 situated a little more than one-third of the body length from the 

 anterior end. The oral collar, 0.29 to 0.34 mm. wide, is kidney- 

 shaped, its ventral notch measuring 0.11 to 0.12 mm. in width and 

 its dorsal space 0.08 to 0.10 mm. The collar spines number 12 on 

 each side (total 24) and are 0.046 to 0.054 mm. long and 0.011 to 

 0.015 mm. wide at their bases. The innermost ventral and inner- 

 most dorsal of these spines are usually a little shorter than the 

 others. The second ventral spine on one or both sides (numbered 

 from the median line) is often found in front of the row (fig. lA), 

 but sometimes it is in line with the rest, in which case the first and 

 third may be placed somewhat behind. 



The testes possess crenated margins, are oval in shape, elongated 

 transverseh^^, one placed in front of the other with their neighbor- 

 ing surfaces in close contact. The anterior testis measures 0.09 to 

 0.16 mm. long by 0.19 to 0.24 mm. wide; the posterior 0.13 to 0.18 mm. 

 by 0.16 to 0.23 mm. The two vasa efferentia are given off from their 

 antero-external borders, pass anteriorly on the dorsal side of the 

 acetabulum and empty into a bent, pj'^riform vesicula seminalis. 

 A thin cirrus sac, which lies anterior to the center of the acetabulum, 

 surrounds the seminal vesicle and short ejaculatory duct. A wide 

 genital sinus, into which the male and female canals open, is located 

 3136— 22— Proe.N.M. Vol.60 41 



