448 
PACIFIC SCIENCE, VoL VII, October, 1953 
4. Acetabulum near cecal bifurcation 
S. callyodontis 
Space between acetabulum and cecal bi- 
furcation nearly twice length of acetabulum 
V sigani 
SYSTEMATIC POSITION 
Liihe (1906: 102) and subsequent authors 
have associated the genus Schistorchis Liihe, 
1906, with the genus Pleorchis Railliet, 1896. 
Johnston (1913: 383-386) named Pleorchis oli- 
gorchis which Odhner (1928: 5) considered 
identical with the previously described Schis- 
torchis carneus. Stunkard (1931: 713-714) 
quoted the latter paper, apparently in agree- 
ment. Yamaguti (1942: 362) referred to 
'' Schistorchis oligorchis (Johnston, 1914) 
[correctly 1913] which is very closely related 
to if not identical with, Schistorchis carneus,'' 
seeming to have reached the conclusion in- 
dependently. Manter and Van Cleave (1951: 
331) likewise referred to Pleorchis oligorchis 
Johnston, 1914 [sic] . . . transferred to Schis- 
torchis by Yamaguti (1942).” 
Poche (1926: 1-458) placed the genus 
Schistorchis with Pleorchis in the family Ple- 
orchiidae where it remained until 1942. Cable 
and Hunninen (1942: 306) observed that ”the 
genera Pleorchis and Schistorchis for which 
Poche (1925) [correctly 1926] erected the 
family Pleorchiidae, do not seem to be at 
all closely related” and considered Pleorchis 
among the Acanthocolpidae. Nothing was 
suggested for Schistorchis, 
At very nearly the same time, Yamaguti 
(1942: 364) proposed the separation of Ple- 
orchis and Schistorchis and erected the new 
family Schistorchiidae to include Schistorchis, 
and also Apocreadium Manter, 1937, and Cho- 
anodera Manter, 1940, which he considered 
to resemble Schistorchis closely. Both Choano- 
dera and Apocreadium were considered by 
Manter (1940: 344-348) as members of the 
family Gyliauchenidae. Cable and Hunninen 
(1942: 309) considered the gyliauchenids as 
related to Lepocreadiidae, and Manter (1947: 
264) stated that '^Apocreadium and Choanodera 
are so similar to Homalometron (differing chief- 
ly in their lymphatic vessels) that they should 
be transferred to the Homalometroninae, fam- 
ily Lepocreadiidae.” Thus Schistorchis is the 
only remaining genus in the family Schistor- 
chiidae. 
The genus Schistorchis agrees very well with 
the description of Homalometroninae in the 
family Lepocreadiidae Nicoll, 1934, as pro- 
posed by Cable and Hunninen (1942: 308). 
Although this is the first report of multiple 
testes among the Homalometroninae, they 
are present among the Lepocreadiinae and are 
provided for in the description of the family. 
The presence or absence of ani is often 
difficult to determine in a whole mount. Both 
Schistorchis callyodontis and S. sigani were de- 
scribed from a single specimen. Both Liihe 
and Johnston described S. carneus without ani, 
but Odhner (1928: 5) found them to be pres- 
ent when he sectioned specimens. Stunkard 
(1931 : 723-724) observed that secondary con- 
nections between the intestinal ceca and the 
exterior have developed independently in sev- 
eral different families and that such commu- 
nications are not uniformly present in all 
members of those families in which they do 
occur. The conclusion was drawn that such 
connections are relatively recent acquisitions 
which developed after the families became 
differentiated. 
It is proposed that the genus Schistorchis be 
classified as Homalometroninae, family Lepo- 
creadiidae, and that the family Schistorchiidae 
become a synonym of Lepocreadiidae. 
Schistorchis stenosoma n. sp. 
Fig. la-d 
HOST: Cantherines pardalis (Ruppell), file 
fish; in all of 7 specimens examined. 
location: Intestine. 
DESCRIPTION (based on a series of 31 spec- 
imens) : Body 7 or 8 times longer than wide, 
1.701 to 4.271 mm. long, 0.211 to 0.635 mm. 
wide; width about equal along most of body 
length, but slightly wider immediately ante- 
