251 
Proboscis usually slightly longer than wide, provided with three circles 
of six hooks each. Hooks of terminal circle provided with a conspicuous 
reflexed root-process approximately one-half the length of the hook 
proper. Terminal hooks 94 to 120 » long. Middle circle composed of 
hooks 41 to 83 » long, with one short basal process extending anteriorly 
and another posteriorly from the point of origin of the hook proper. 
Basal hooks 30 to 71 » long with no conspicuous root, frequently with a 
small process similar to the one described for the hooks of the middle 
circle. Embryos within the body of gravid female approximately ellip- 
tical, 26 to 41 » long by 12 to 15 » in diameter. Testes two, approximately 
elliptical, in broad contact with each other; followed posteriorly by a 
syncytial cement-gland containing eight giant nuclei. 
Type host, Mugil cephalus ; intestine infested. 
Type locality, Spezia, Italy. 
Distribution—The writer has already (1913 :188) called attention 
to the fact that records by Linton of the occurrence of this species in 
North American fish are based upon misidentifications. It is interesting 
to note that while Mugil cephalus and other species of the same genus 
occur along the Atlantic coast of North America, no Acanthocephala have 
been reported from any of them in Linton’s extensive records of the 
examinations of marine fish for parasites. 
The reports of N.agilis from Scotland by Thomas Scott and from 
France by Dujardin are the only other reports known to the writer of the 
supposed occurrence of this parasite outside the Mediterranean region. 
Of these, Scott’s identification is not at all certain. General appearance 
of the parasite and the species of the host were the only two points which 
caused him to place his specimens under this name. His figures are clearly 
enough of a species of Neoechinorhynchus, although they are not dis- 
tinctive or definite enough to justify the assumption that they represent 
N. agilis. 
It seems probable that N. agilis is restricted in its distribution to the 
fishes of the genus Mugil in the Mediterranean region. 
NEOECHINORHYNCHUS RUTILI (Miller, 1780) 
Of the fresh-water representative of this genus in Europe, the writer 
has not been able to secure specimens for study. European investigators 
seem inclined to agree with Ltthe in regarding Echinorhynchus clavaeceps 
as a synonym of N. rutili. This last species thereby becomes the only valid 
species of the genus reported from fresh-water fishes of central Europe. 
This claim of synonymity is obviously based upon a literature study rather 
than upon examination of type specimens of the species concerned. Much 
of the work of European investigators has unfortunately been of this 
character. It is certain that none of the early descriptions, dating back 
more than a century, include data which, alone, would suffice to differ- 
entiate species of the family Neoechinorhynchidae. The following table 
indicates typical discrepancies in the data recorded for N. rutili (= E. 
clavaeceps). 
