148 Wisconsin Academy of Sciences, Arts, and Letters. 
The oral sucker is small; the pharynx is almost 1% times as 
long as wide; esophagus, very slender, about three times as long 
as pharynx; intestinal rami, thick, extending to posterior end of 
the body. 
Vitelline glands are in contact with the lateral surfaces of the 
intestinal rami, extending from the acetabulum to the tips of the 
rami; a duct from each group of glands extends directly across 
the body to the middle where it unites with that from the opposite 
side and enters a rounded yolk reservoir. 
The testes are somewhat lobate and elongated antero-posteriorly. 
They lie between the intestinal rami and the posterior, median 
excretory duct. Cirrus sac: very small and ovate. The ovary lies 
just anterior to the vitelline ducts. It is lobate and elongated. 
The uterus is filled with eggs and occupies the space between the 
intestinal rami, from the acetabulum to the posterior end of the 
body. 
The bullheads in Lake Pepin were often infected with this 
trematode. Figure 6 was drawn from a specimen taken from the 
swim bladder of Ameiurus melas, July 12, 1920 (U. S. Nat. Mus., 
Cat. No. 7618). Other specimens were found in the swim bladders 
of A. natalis and A. nehulosus. Young specimens were found 
encysted in the liver peritoneum of a Schilbeodes gyrinns, June 
23, 1920. 
MACRODEEOIDES, new genus 
Elongated Plagiorchiidae with the two suckers of nearly equal 
size. The genital opening is at the anterior margin of the aceta¬ 
bulum. A slender prepharynx and a longer esophagus are present. 
The intestinal rami arise from the esophagus some distance anterior 
to the acetabulum. The body is covered with sharp spines which 
decrease in size posteriorly. The vitelline glands extend from a 
short distance behind the acetabulum to the posterior testis. The 
genus shows resemblances to Macrodera Loos, Haplometra Loos, 
and Glypthelmins Stafford. 
Type species: Macroderoides spiniferus, Pearse. 
Macroderoides spiniferus, new species 
(Pig. 9) 
Type: Cat. No. 7619, U. S. National Museum; Lake Pepin, 
Wisconsin; July 11, 1920; collector, A. S. Pearse. 
