A Discussion of the Trematode Genus Schistorchis 
(Family Lepocreadiidae) with Descriptions of Two New 
Species from Hawaii^ 
Mary Louise Hanson^ 
This report is the first to be based on spec- 
imens collected during June and July of 1949 
at the Marine Laboratory of the University of 
Hawaii, Honolulu. To Dr. Robert W. Hiatt, 
chairman, and to the members of the Depart- 
ment of Zoology and Entomology at the 
University of Hawaii I wish to extend my 
sincere appreciation for the laboratory space 
and the laboratory equipment which were 
furnished me. To Dr. William A. Gosline, 
ichthyologist in the Department of Zoology 
and Entomology at the University of Hawaii, 
the author is indebted for his invaluable assist- 
ance in identifying the fish hosts. The fishes 
were made available through the generosity 
and assistance of Mr. Spencer W. Tinker, 
Director of the Honolulu Aquarium. From 
all these individuals, and from Dr. H. W. 
Manter under whose direction the work was 
done, the author has received valued encour- 
agement. The trip to Hawaii was made pos- 
sible by a Robert A. Wolcott Scholarship 
granted by the University of Nebraska Foun- 
dation. 
The trematodes, upon removal from the 
hosts, were killed under a cover glass with 
F.A.A. fixative (formalin, alcohol, and acetic 
acid). Storage for a short time was in 70 per 
cent alcohol. The worms were stained in De- 
lafield’s haematoxylin, cleared in xylol, and 
mounted in Permount. 
1 Studies from the Department of Zoology, Univer- 
sity of Nebraska, No. 261. 
^ University of Nebraska State Museum, Lincoln. 
Manuscript received July 22, 1952. 
Type specimens are being deposited at the 
United States National Museum. 
The genus Schistorchis Liihe, 1906, now rec- 
ognized to be quite distinct from Pleorchis 
Railliet, 1896, with which it was once asso- 
ciated, has the following characteristics: me- 
dium to large, elongated Homalometroninae; 
smooth or spined anteriorly; oral sucker ter- 
minal or subterminal; ceca long, with or 
without ani; excretory vesicle I-shaped with 
long collecting tubules often reaching pha- 
ryngeal level; genital pore median or very 
slightly to the left, just anterior to the ace- 
tabulum; cirrus sac absent; genital sinus pres- 
ent; eleven testes intercecal, tandem in a single 
row or arranged more or less in a double row; 
ovary pretesticular, median or to the right; 
seminal receptacle and Laurer’s canal present; 
uterus not extending posterior to the ovary; 
parasites of marine fishes. Type species: S. 
carneus Liihe, 1906. 
In addition to the type species the genus 
contains four species: 6. callyodontisY dirndigun^ 
1942; 5. sigani YdiVnd^gMU, 1942; 5. stenosoma; 
and S. zancli. The latter two species are here 
described. The following key to the genus 
Schistorchis is proposed: 
1. Testes not in a single median row 3 
Testes in a single median row. ........ 2 
2. Uterus preovarian .6. zancli 
Uterus reaching at least to mid-ovary . . . . ■ 
. 5. stenosoma 
3. Testes not in two lateral, opposite' groups 
. .4 
Testes in two lateral, opposite groups .... 
5. carneus 
447 
