ENTOZOA OF MARINE FISHES. 
525 
On account of the complicated muscular system of the Acanthocephala 
there is a decided tendency to contract unequally when placed in the 
killing fluid. In the case of E. acus I have succeeded in preserving 
specimens in the best condition for histological study by first placing 
them for a short time in fresh water, after which they may be transferred 
to any of the ordinary hardening fluids. Specimens may be killed in a 
weak solution of chromic acid, in which they continue to live for several 
hours in good condition for histological work. I have had excellent 
results also in the use of osmic acid. 
Mr. V. N. Edwards, of Wood’s Holl, Massachusetts, has rendered me 
valuable service in procuring specimens. 
Order ACANTHOCEPHALA Pvudolphi. 
Genus Echinorhynchus Zoega. 
Echinorhynchus acus Rudolphi. 
[Plate i, figs. 1-11, and Plate vra, figs. 89-90.] 
U. S. F. C. Rept. 1886, pp. 492,493, plate v, figs. 7-13. 
This species was recorded in the paper referred to above from Para - 
lichthys dentatus. I have referred to this species several finds of Echin- 
orhynchi from a variety of hosts. These, while differing greatly in shape 
and size, agree closely iu'all essential characters. 
Since my first paper was submitted I have noted the occurrence of 
this parasite on several occasions, as follows : 
No. 
Date. 
Name of host. 
No. of 
fish ex- 
amined 
No of 
Echinor- 
hvnchi. 
1886. 
1 
Aug. 6 
Prionotus evolans 
1 
1 
2 
Aug. 6 
Lophius piscatorius 
1 
9 
3 
Aug. a 
Gadus morrhua 
17 
4 
Aug. 8 
Melanogrammus seglefinus 
85 
5 
Aug. 10 
Pseudopleuronectes americauus 
1 
76 
6 
Oct. 4 
Paralichthys dentatus 
1 
10 
7 
Oct. — 
Roccup lineatus 
85 
8 
Oct. — 
Pseudopleuronectes americanus 
x 
85 
9 
Oct. 13 
do 
1 
75 
10 
Oct. — 
do 
41 
11 
Oct. 7 
do 
192 
1887. 
12 
J uly 21 
Prionotus evolans 
1 
1 
13 
Aug. 10 
Pseudopleuronectes americanus 
17 
116 
14 
Aug. 10 
Paralichthys dentatus 
1 
15 
Aug. 29 
Pseudopleuronectes americanus 
1 
42 
16 
Aug. 30 
Paralichthys dentatus 
4 
160 
17 
Sept. 6 
Limanda ferruginea 
12 
64 
1889. 
18 
July 16 
Pseudopleuronectes americanus 
1 
1 
19 
July 23 
— do 
14 
Numer- 
20 
July 23 
Cottus seneus 
1 
ous. 
1 
21 
Aug. 8 
Pseudopleuronectes americanus 
4 
621 
22 
Aug. 8 
Limanda ferruginea 
1 
2 
Remarks. 
Wood’s Holl, Mass. 
Vineyard Sound, near GayHead. 
U. S. F. O. str. Albatross. Collected 
by Mr. Thomas Lee. 
Do. 
Wood’s Holl, Mass. 
No. 1509, Block Island : collected by S. 
E. Meek, at Fulton Market, N. Y. 
Collected by S. E. Meek, at Fulton 
Market, N. Y. 
No. 1525, S. E. Meek. 
No. 1506, S. E. Meek. 
No. 1521, S. E. Meek. 
Collected by V. N. Edwards, Wood’s 
Holl, Mass. 
Wood’s lloll, Mass. 
Do. 
Do. 
Do. 
Do. 
Do. 
Collected by Dr.B. Sharp, Wood's Holl. 
157 from one host. 
Specimen more slender than those 
from P. a meric anus, but resembles 
them in all essential points. 
Collected by V. N. Edwards. 
Do. 
