NO. 14 MANTER: DIGENETICTREMATODES OF FISHES 393 



Body spination to about level of ovary vi^ith traces as far back as testes. 

 Oral sucker 0.262 in diameter; acetabulum 0.397 in diameter; sucker 

 ratio about 3 :4.5 ; acetabulum with narrow transverse aperture. Oral 

 spines 38 or 40 (probably 38 — count uncertain), with 2 pairs of smaller 

 spines in the midventral area. Smallest (midventral pair) 0.048 by 0.010; 

 adjacent pair 0.051 by 0.012; largest spines (lateral and dorsal) 0.110 

 by 0.017. Prepharynx longer than pharjmx; pharj'nx more or less pyri- 

 form, 0.300 long by 0.165 wide; short esophagus; ceca to near posterior 

 end, probably uniting with excretory vesicle. Testes narrow and elongate, 

 tandem, intercecal, in posterior third of body, close together and almost 

 touching but separated by a very few vitelline follicles. Cirrus sac slender, 

 slightly sinuous, extending about ^ distance between acetabulum and 

 ovar>'; cirrus short, spiny, opposite posterior half of acetabulum; genital 

 atrium opposite anterior half of acetabulum; genital pore median at an- 

 terior edge of acetabulum. Ovary subtriangular and elongate, median, 

 well anterior to testes from which it is separated by many vitellaria; 

 uterus long but with narrow intercecal coils, uterine area (to metraterm) 

 more than ^ total body length. Metraterm considerably shorter than 

 cirrus sac, ending at anterior level of seminal vesicle. Vitellaria abundant, 

 dorsal, ventral, and lateral to ceca; ventral to uterus; continuous from 

 posterior end of cirrus sac to posterior end of body, filling space between 

 ovary and testes but barely meeting between testes. Eggs 60 to 65 by 

 31 to 37 /A. 



The name longisomum refers to the very long hindbody which is 

 8 times the length of the forebody. 



Comparisons. The presence of smaller oral spines in the midventral 

 region groups this species with S. hicoronatum, S. cesticillum, and S. meg- 

 acephaluTTij which are the only other species with ventrally interrupted 

 rows of oral spines. It is distinctly different from S. megacephalum (col- 

 lected from the same host) in body size and proportions, in sucker ratio, 

 in number of oral spines, in shape of testes, and in position of the ovary in 

 relation to the testes. It is more like S. bicoronatum and S. cesticillum in 

 body size and body proportions, although its hindbody is relatively longer. 

 It differs from both in the anterior extent of the vitellaria (which do not 

 extend be3'ond the base of the cirrus sac), in posterior extent of the cirrus 

 sac (which does not reach nearly so far toward the ovary), in smaller 

 eggs, and in a slightly larger number of oral spines. The testes are closer 

 together than in S. cesticillum; the ovary is more distant from the testes 

 than in S. bicoronatum. 



