414 
PACIFIC SCIENCE, Vol. XIV, October I960 
Opecoelus lanceolatus n. sp. 
Figs. 7, 8, 9 
SPECIFIC DIAGNOSIS: Based on four speci- 
mens. Body elongate, narrow, smooth, 1.86-3.08, 
av. 2.4 long, and 0.364-476, av. 0.394 maximum 
width; oral sucker subterminal 0.096-112, av. 
0.106 long, and 0.096-112, av. 0.103 wide; 
acetabulum with five pairs of dactyls or papillae, 
the three median pairs longer than others, 
acetabulum 0.1 6-. 172, av. 0.164 long, and 0.16 
wide; prepharynx short; pharynx oval, 0.064- 
.08, av. 0.078 long, and 0.04-.058, av. 0.049 
wide; esophagus approximately as long as phar- 
ynx; ceca extend laterally and posteriorly to join 
near the posterior end of body, rectum short, 
anus ventral, near posterior end of body; gonads 
in middle third of body, ovary pretesticular, 
oval to slightly indented; Mehlis gland diffuse, 
FIG. 7. Opecoelus lanceolatus, dorsal view. 
Fig. 8. O. lanceolatus, terminal genital organs. 
Fig. 9- O. lanceolatus, side view to show dactyls on 
acetabulum. 
immediately anterior to ovary; Laurer’s canal 
present; seminal receptacle lacking; uterine coils 
intercecal, mainly between ovary and acetabu- 
lum; metraterm short but slightly longer than 
cirrus sac; vitellaria extend from a short distance 
posterior to the acetabulum to the posterior end 
of body where they unite, mainly extracecal 
but slightly invading intercecal zone anterior 
to ovary and conspicuously between the testes 
and posterior to them; eggs yellow, operculate, 
0.042-.048, av. 0.047 long, and 0.029-.032, av. 
0.031 wide; testes tandem, one or both with 
indentation in posterior margin, anterior testis 
0.179-288, av. 0.24 long, and 0.09-238, av. 
0.188 wide; posterior testis 0.192-32, av. 0.232 
long, and 0.1 12-224, av. 0.184 wide; seminal 
vesicle elongate, tubular, usually extending pos- 
terior to the acetabulum at least the diameter 
of the latter organ; cirrus sac short, enclosing 
prostatic cells and a weakly developed cirrus; 
common genital pore on left side of body, at or 
near posterior pharyngeal level; excretory vesicle 
tubular, reaching to or near ovary, opening 
terminally. 
HOST: Mulloidichthys samoensis (Gunther), 
a goatfish. Four of ten fish infected. 
LOCATION: Intestine. 
LOCALITY: Kaneohe Bay, Oahu, Hawaii. 
TYPE SPECIMEN: Opecoelus lanceolatus , de- 
posited as no. 5612, Hancock Parasitology 
Collection. 
Opecoelus lanceolatus seems to be closest to 
0. xenistii Manter, 1940, found in the intestine 
of Xenistius calif orniensis (Steindachner) col- 
lected at Tagus Cove, Albemarle Island, Gala- 
pagos. It differs from O. xenistii in the follow- 
ing ways : the vitellaria do not extend anteriorly 
as far as the acetabulum, the metraterm is much 
shorter, and the ovary is not trilobed. 
Pseudopecoeloides tenuoides n. sp. 
Figs. 10, 11 
specific DIAGNOSIS: Based on eight speci- 
mens. Body elongate, slender, smooth, some- 
what constricted at gonad levels, 2.555-5.04, av. 
3.47 long, and 0.16— .5, av. 0.3 wide; oral sucker 
subterminal 0.22-28, av. 0.243 long, and 0.18- 
.23, av. 0.193 wide; acetabulum pedunculate 
