286 
CARNEGIE INSTITUTION OF WASHINGTON 
eggs from one female of Panulirus argus, 4 of Acanthocarpus alexandri, 1 of 
Stenocinops spinosissima, 3 of Portunus spinicarpus, and 9 of Mithrax 
verrucosus. 
Effects of Selected Indophenol Dyes on Fishes, by Warren Reed Lewis 
Tadpoles which develop in solutions of certain of the phenol indophenol 
dyes lose the pigment from the skin and also from the eyes (M. R. Lewis). 
Therefore it was thought interesting to see whether these dyes could bring 
about a similar destruction of the pigment of other types of animals, par¬ 
ticularly of the marine fishes. 
Investigations were undertaken at the Tortugas Laboratory in collabora¬ 
tion with Mr. W. R. Kenny who prepared a number of dyes with these 
experiments in view. The dyes used were o-chlor phenol indophenol, phenol 
indophenol, both the Na salt and the free acid forms, and 1 naphthol 2 
sulphonate indophenol which give a range of reduction potential from 
+0.233 to +0.123. The concentrations used were 1:100,000 and 1:200,000. 
Members from 4 families of fish were used: Halichoeres bivittatus (Bloch), 
Bathygobius soporator (Cuvier and Valenciennes), Malacoctenus moorei 
(Evermann and Marsh), Pomacentrus analis (Poey). 
No changes were observed in the living fish after four weeks, even though 
the concentrations of the dyes used in these experiments were much stronger 
than those used in the experiments on developing tadpoles. 
The results seem to indicate that the dye did not penetrate the skin. 
However, in order to determine this, the preserved materials will be pre¬ 
pared in sections for microscopical observation, and in addition some of 
the sections will be oxidized to show whether any of the dyes may have 
passed through the epidermis in a reduced form. 
A few types of invertebrates were tried but none survived under the con¬ 
ditions of the experiments. 
Observations Upon Tortugas Fishes, by W. H. Longley 
Chiefly as an incidental result of dredging undertaken for other purposes, 
several species have been added as usual to the local fish fauna as a result 
of the summer's work. There has not yet been opportunity to identify all 
precisely. The list includes at least these: Antennarius spp., Chcetodon ay a, 
Cryptotomus roseus, Epinephelus niveatus, Gillellus sp., Gymnachirus fasci- 
atus, Porichthys porissimus and Scorpcena inermis. 
Information has also been obtained upon a matter which attracted atten¬ 
tion a year ago. Specimens of Prionodes phoebe and two other unnamed 
species of the genus, to the number of 40 in all, collected at different times 
and places, were without exception apparent females. Actually, it appears 
now, all three species are normally hermaphroditic. Active sperm cells in 
abundance have been taken from fishes of the two unnamed species whose 
eggs were at the same time almost ripe. Specimens of P. phoebe examined 
were not so nearly sexually mature and gave a less satisfactory demon¬ 
stration of its bisexuality. It is to be anticipated, however, that the her¬ 
maphroditic condition prevails widely in the genus, for 11 mature specimens, 
distributed among four other species which there has been opportunity to 
examine, are also to superficial examination females only. None has a 
normal testis. 
Actually the condition is by no means confined to the genus Prionodes. 
Diplectrum bivittatum —a species perfectly distinct from D. radiate, with 
which it has been confused—is also a functional hermaphrodite from which 
TORTUGAS LABORATORY 
287 
I have had living sperm cells, together with eggs almost or quite mature. 
Diplectrum formosum is not mature at Tortugas at the end of August, but 
its immature gonads are all of one type, resembling immature ovaries. 
Four sexually mature museum specimens contained eggs, and one examined 
closely showed between the lobes of the gonad and behind the point of 
their union on the ventral side just such a mass of tissue as in D. radiale, 
and, in the species of Prionodes in life, yields sperm. 
Hypoplectrus is another genus which, with little doubt, will prove to be 
like these in its mode of reproduction. I have seen 17 ovigerous museum 
specimens but no definitive males. Again the gonad of a specimen closely 
examined showed proximally on the ventral side a region resembling that 
from which the sperms of the other hermaphrodites come. In two of Poey’s 
types in the Museum of Comparative Zoology this apparent spermatogenous 
tissue extends distinctly upon the lateral face of the gonad. 
Dules auriga with 8 ovigerous specimens but none with normal testes 
promises to be another of the same sort. In any case, these observations 
with those of others show that normal hermaphroditism occurs very com¬ 
monly among the lesser Serranidse, though the conclusion does not apply to 
the genus Pronotogrammus. 
A part of the summer was devoted to study of the bathymetric distribu¬ 
tion of fishes within the 600-fathom line, but much the greater portion was 
spent in checking and organizing for publication data regarding species 
known from within the 100-fathom line. A note upon progress made will 
be found elsewhere in this volume. 
Continued Studies on Trematodes of Tortugas, by H. W. Manter 
Examination of fishes of Tortugas for helminth parasites has been con¬ 
tinued another summer, this season with the assistance of Dr. O. L. Wil¬ 
liams. Approximately 2400 fishes including 272 species have now been ex¬ 
amined, almost all of them individually. Of the species of fishes, 80 per 
cent are subject to trematode infection. About 60 additional species of 
trematodes were added to the Tortugas list during the summer, bringing 
the total number to over 210 species from fishes alone. Of these, 
approximately 33 are monogenea. A large number of the fishes were se¬ 
cured by trawling at varying depths down to and including 582 fathoms. 
At all these depths the fishes were found to be more or less infected with 
trematodes and the indication is that the fairly deep ocean is well populated 
with these parasites. 
Many new host records were secured. These, it is hoped, will contribute 
to correct understanding of specificity and distribution within this group 
of parasites. Knowledge of bathymetric distribution of certain trematodes 
is also growing. It is clear that there are rather definite vertical limits 
varying with the species. Most of the deeper-water forms belong to dif¬ 
ferent species than those found near the surface, and enough collections 
have been made to give considerable significance to the upper and lower 
limits of occurrence. 
Among the few species of trematodes of Tortugas also occurring north 
to Woods Hole is the form described from Beaufort by the author as 
j Rhagorchis odhneri Manter 1931 (Parasitology, vol. 23, pp. 405-406). 
This species is, in reality, the same as the Distomum pallens Rud. of Linton 
1898 (Proc. U. S. Nat. Mus., vol. 20, p. 526) and the correct name for the 
species depends on the confirmation of identity with Rudolphi's form. 
The distribution of Distomum fenestratum at Tortugas is exceedingly 
wide. The parasite occurs, always in juvenile form, in many (at least 
