164 Papers from the Marine Biological Laboratory at Tortugas. 
recording under the name D. monticelii; those from the sardine were few 
and agree with D. appendiculatum. 
Many of the species are represented in the collection by but one or at 
most few specimens, and it may be advisable to refrain from giving them 
names until more material is secured. 
A distome, probably represented by more than one species, found in most 
of the lots of gray snappers, grunts, and groupers, is unique in that the 
ova, as they lie in the folds of the uterus, present a wreath-like appearance, 
and each ovum has a long, slender filament, such as is common on the ova 
of monogenetic trematodes. 
Trematodes were found in large numbers in only two instances, a black 
angel-fish, examined July 18, and a loggerhead turtle, examined July 1. 
In general it may be said that the trematode fauna of Tortugas is rich 
in species. 
Ectozoa.—Parasitic Isopods were found on the sting-ray, cabezote, 
yellow-finned grouper, and a small shrimp common in the gulf-weed. 
Parasitic Copepods were found on only one fish, the Spanish sardine. 
One leech,’ colored vivid green and red-brown with blotches of white, 
was found on the tongue of a nurse-shark. 
General Observations——The groupers of the Tortugas, like those of 
Bermuda, especially the older specimens, are characterized by having more 
or less abundant cysts on the viscera and often in the walls of the stomach 
and intestine. These cysts are, as a rule, dark brown, often nearly black. 
The color is due to the abundant pigment which is deposited in the cyst. 
While these cysts are more often than otherwise due to cestodes, accumu- 
lations of pigment and degenerate connective tissue were also found asso- 
ciated with other entozoa, viz, nematodes and acanthocephala in Bermuda, 
and nematodes in Tortugas. 
It is perhaps worthy of remark that the great barracuda, which is a 
very voracious and predatory fish, appears to harbor but few parasites, 
either as a final or intermediate host. This conclusion is warranted also 
from the results of the examination of 5 barracuda in Bermuda in 1903. 
The largest Tortugas specimen measured about 1.5 meters in length; the 
Bermuda specimens were about one-half that length. 
It would be of interest to know whether the apparent immunity from 
parasites of the barracuda and other fish is correlated in any way with 
the digestive ferments. 
I take advantage of the opportunity offered by the passage of the proof 
of this paper through my hands to add the following extract from the pre- 
liminary report on the results of my work at the Tortugas laboratory in the 
summer of 1907 (Year Book No. 6, p. 114). 
No selachians were taken while I was at the laboratory this year. One 
small nurse-shark (Ginglymostoma cirratum) had been taken before my 
arrival, from which were obtained a few specimens of a species of Ascaris, 
not found last year. After I left the laboratory, Mr. Davenport Hooker 
collected from a cub-shark (Carcharhinus lamia) some cestodes, which I 
have since examined. As I have already made a report on the cestodes 
* This has been identified for me by Dr. J. Percy Moore as Pontobdella muricata, 
a widely distributed parasite of selachians. 
