247 
Rudolphi’s description of N.agilis (= Echinorhynchus agilis) was 
based upon an examination of nine individuals taken from the intestine 
of Mugil cephalus at Spezia. The above-mentioned alcoholics from the 
Berlin Museum (Catalog No. 1179) had in the vial with them a label indi- 
cating that they were “types” of Echinorhynchus agilis from the collection 
of Rudolphi. It is very apparent that the term type specimens was here 
used in the older meaning of the term, indicating a type-lot of material 
upon which a specific description was based, not referring to a single 
individual. In spite of the fact that these specimens had been preserved 
in alcohol for almost a century they were in good condition for examina- 
tion. Because of the difficulties involved in the technic of dehydrating 
and clearing Acanthocephala, and because of the uncertainty of the suc- 
cess accompanying this procedure with such a limited number of unre- 
placeable specimens, the writer confined his examination to those obser- 
vations which could be made upon the specimens while in alcohol. 
Unfortunately, the individuals were both males, and consequently no 
facts regarding the embryos were available. The proboscis, fortunately, 
was extended fully in both specimens. The body of only one of the worms 
was perfect, the other lacking the posterior region of the body. In Table 
III the perfect individual is referred to as 1179A; the mutilated one, as 
1179B. Careful observations were made upon the proboscis hooks of these 
specimens, but since the specimens were not cleared, measurements of 
hooks could be obtained for only those portions protruding beyond the 
proboscis-wall. As shown in the table, the two individuals differed con- 
siderably in the length of the exposed portions of the hooks (see also PI. 
XXVIII, Fig. 42, 43). It is interesting to note that this type material 
furnishes the key to an understanding of the variability in hook-length 
found for different individuals of this species as brought out in a later 
part of this paper. 
TABLE III 
DATA FROM Stupy or “Type” MATertar or N. agilis (Rud.) 
Length, exposed portion of hooks 
| Proboscis | 
Body-length| | | | 
| Length | Width | Terminal Middle Basal 
a4 | | 
| | a a1 iB 
1179 A 33mm. | 160m | 148, 49 ig | °10p 
1179B _|Incomplete | 148 w | 153 uw 54u 21-27 | 20 u 
Comparison oF N. agilis DATA FROM VARIOUS SOURCES 
Through the generous response of Professor Corrado Parona, of 
Genoa, and of Professor Fr. Sav. Monticelli, of Naples, the writer was 
supplied with collections for comparison with the “type” specimens 1179A 
and 1179B. The close resemblance between alcoholic specimens received 
