A NEW INTESTINAL TREMATODE OP MAN. 391 



Shell gland well developed, situated between ovary and anterior testicle. Uterus 

 coiled in the space bounded laterally by excretory channels, anteriorly by aceta- 

 bulum and posteriorly by ovary and shell gland. Ova large, operculated, not 

 very numerous, and develop ciliated miracidium after leaving body of host. 



Host of type species.— Homo sapiens: Habitat; intestine. 



Type species. — Fascioletta ilocana. 



Fascioletta ilocana sp. nov. 



Specific diagnosis. — Fascioletta: Length, 4 to 6 millimeters; maximum 

 Dreadth, 0.75 to 1.35 millimeters; maximum thickness, 0.50 to 1 millimeter; 

 greatest breadth and thickness a little posterior to the caudal border of the 

 acetabulum. Posteriorly, the body attenuates gradually throughout two-thirds 

 its length to a rounded caudal extremity ; anteriorly, for about one-third its 

 length, to a rather sharper cephalic extremity. In the posterior half the body 

 becomes increasingly flattened toward the caudal end. Oral sucker terminal or 

 slightly ventro-subterminal, small ( 130 to 200 /j. transversely by 75 to 130 /i 

 deep) ; dorsal lip much larger than ventral, giving the sucker a ventral inclina- 

 tion. Ventral acetabulum about three times as large as oral sucker (nearly 

 globular, 480 to 518 ii in diameter), situated with its center at about the junc- 

 tion of the first and second anterior fifths of the body length. Skin smooth 

 and without spines. Pigmentation slight and evenly distributed. Prepharynx 

 from 10 to 63 /i long. Pharynx globular, from 150 to 190 /a in diameter. 

 GGsophagus short (50 to 100 ,u). Intestinal bifurcation immediately anterior 

 of plane passed through genital pore. Intestinal caeca thin-walled; follow rather 

 closely the lateral margins of body to near its posterior end, being partly 

 inclosed by the vitellaria throughout considerably more than the posterior half 

 of their course. Genital pores open upon the surface separately to the left of 

 the median line and slightly posterior of a plane midway between posterior 

 border of pharynx and anterior border of acetabulum. Male organs: The cirrus 

 pouch is from 560 to 608 /j. long by from 240 to 280 fi broad; situated antero- 

 dorsad of the acetabulum, with its longitudinal axis directed antero-ventrally 

 and slightly to the left. Posteriorly it contains a bladder-like vesicula seminalis 

 which receives, the vasa deferentia and gives origin to a well developed cirrus 

 which takes a more or less coiled course to the male genital pore through which 

 it may protrude in from one to two spiral turns. Vasa deferentia divergent. 

 The testicles lie one immediately and directly behind the other, occupying the 

 median field just caudad of the transverse vitello-ducts. Each testicle is more 

 or less distinctly divided into an anterior and posterior lobe by a transverse, 

 circular constriction, and other slight indentations of the surface may indicate 

 ill-defined secondary lobules. Female organs : Ovary globular, situated at equator 

 of body, slightly to right of median line. Vitellaria highly developed, extending 

 antero-posteriorly from the caudal extremity to a plane midway between proximal 

 borders of ovary and acetabulum. Cephalad of the posterior border of the tes- 

 ticles they lie along the extreme lateral margins, filling the space between margins 

 and caeca and extending somewhat upon the dorsal and ventral surfaces, thus 

 inclosing the caeca dorsally and ventrally between the two superficially placed 

 vitellogen layers. Caudad of the testicles, the vitellaria spread over the dorsal 

 surface and meet in the median line, at the same time gradually encroaching 

 upon the median field ventrally. In the extreme posterior portion of the worm 

 (about one-tenth of its total length) they may meet in the median line ventrally 

 as well as dorsally, thus completely inclosing the caudal extremities of the caeca 

 and excretory tract. At the anterior border of the anterior testicle the trans- 

 verse vitello-ducts pass inward and slightly forward to the well-developed, 



