479 
In Amia calva Linn. and Lepisosteus platystomus Raf., Havana, 
Illinois. All material is from collection of Dr. H. B. Ward. 
Proteocephalus singularis nov. spec.: — With characters of genus. 
Strobila as much as 17 cm long by 0,90—1 mm broad. Head small 
0,25—0,30 mm broad by 0,20-—0,22 mm long, bearing four large 
suckers at broadest zone. Suckers separated by deep grooves. 
Apical region of head frequently prolonged into a slender unarmed tip. 
Suckers somewhat variable in outline but always with pointed apex, with 
shallow cavities and thin muscular walls. Length of suckers 0,13 to 
0,17 mm, breadth 0,17—0,19 mm. No fifth sucker, nor vestige of same. 
Neck slender, 2—3 mm long. First proglottids much broader than 
long. Mature proglottids about twice as broad as long, ripe ones lon- 
ger than broad or quadrate. Segmentation evident. 
Genital pore as in P. perplexus. Testes 75—90, in one layer. 
Cirrus slender, straight, muscular. Cirrus-pouch slender, 0,185 to 
0,265 mm long, reaching !/,—2/, across proglottid breadth. 
Vagina always anterior to cirrus-pouch and never crossing latter. 
Beginning region of vagina constricted, constriction terminating at 
sphincter vaginae situated 0,1 mm from opening of vagina. Beyond 
sphincter vaginae a dilatation. Vagina not ciliated. Vitellaria not 
extending along posterior border of proglottid. Vitelline follicles large. 
Uterus with 20—25 lateral pouches on either side and with 2—4 ven- 
tral pores. Embryos 0,014—0,0156—0,0168 mm, second egg-membrane 
0,026—0,031 mm, outer membrane 0,027—0,033 mm in diameter. 
Excretory vessels very sinuous. Dorsal vessel much smaller than 
ventral. 
. In Lepisosteus platystomus Raf., Havana, Illinois. All material is 
from Dr. H. B. Ward’s collection. 
Choanoscolex nov. gen.: — This genus is characterized by the fold 
of tissue at the base of the head and within which the head and suckers 
may be partially or wholly withdrawn. Sexual organs as in Proteoceph- 
alus. Ichthyotaenia abscisa Riggenbach from Stlurus sp., Rio Para- 
guay, is the type of the genus. There are no other known species in 
this. genus. 
Crepidobothrium Monticelli: — This genus has but a single species. 
©. gerrardi (Baird), synonyms of which are Taenia eunectes A. J. Smith, 
T. racemosa Diesing (1850) and 7. racemosa Shipley (1905). The 
genus is distinguished from Ophiotaenia nov. gen. by its cordate suckers. 
A small non-functioning fifth sucker with avery small cavity which 
communicates with the exterior is situated at the apex of the head of 
C. gerrardui. It is nearly covered by the tissues of the head and is not 
to be seen except in sections. Muscles and basement membrane show 
