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region at the division between neck and proboscis. Body spines of female 
60 to 80 w in length; those of male about 28 ». Embryos within body- 
cavity of gravid females 60 to 80 » long and 12 » in diameter, with middle 
membrane drawn out into attenuated polar capsules. 
Hosts: marine fishes, and “trout” from Baltimore—uncertain as to 
whether marine or fresh-water trout. 
ACANTHOCEPHALUS Koelreuter, 1771 
Generic Diagnosis —Acanthocephala of small to medium size, para- 
sitic as adults in the alimentary canal of fishes and amphibians. Sub- 
cuticula and lemnisci provided with numerous small nuclei. Proboscis 
ovate or a short cylinder. Body proper and neck spineless. Proboscis 
receptacle a two-walled muscular sac inserted at the junction of proboscis 
and neck. Central nervous-system located at posterior extremity of 
proboscis-receptacle. 
A single instance of the occurrence of specimens belonging to this 
genus is on record (Van Cleave, 1915) for the American continent. The 
specimens examined, agree in all essential details with the European 
A. ranae, and have been identified as such by the writer. 
ACANTHOCEPHALUS RANAE (Schrank, 1788) 
Proboscis short, slightly larger in the middle than at extremities; 
armed with twelve to twenty longitudinal rows of four to seven hooks 
each. Largest hooks, near the middle of the proboscis, 77 to 80 p» long; 
hooks at anterior tip of proboscis about 60 » long; those in basal row 30 
to 50 ». Embryos within body-cavity of gravid female about 110 » long 
by 13 p» in diameter. 
Host, Diemyctylus viridescens Raf.; Franklin Falls, Baltimore, 
Maryland. 
Family NEOKCHINORHYNCHIDAE 
DISTRIBUTION AND DIVERSIFICATION OF SPECIES 
The Neoechinorhynchidae occur as adults chiefly in the intestine of 
fishes, though one North American species is restricted to the intestine of 
turtles. Hitherto only seven species have been considered as validly placed 
in this family. Of these, two occur in European hosts, while five, accord- 
ing to present records, are confined to the American continent. Recently, 
in examining the collections of Dr. G. R. La Rue taken from Douglas 
Lake, Michigan, the writer discovered an abundance of well-preserved 
material representing two new species of Neoechinorhynchidae, one of 
which clearly belongs to a new genus. Thus, with seven North American 
species, the family seems to have attained a much higher degree of differ- 
entiation on this continent than it has in Europe. This is evidenced not 
only by the greater number of species in the less thoroughly studied 
