Gnathophausia — Pequegnat 
419 
Fig. 14. First abdominal sternite of Gnathophausia 
zoea parasitized by Amallocystis fasciatus. (From Fage, 
1941 .) 
ized G. gracilis is a female of 70 mm body 
length (87 mm including the rostrum) and 
was taken at Station H5 1-406 at a depth of 
0-2926 m. Both parasitized G. ingens speci- 
mens are females, one of which came from 
Station H 5 1-406 (from the same haul which 
captured the parasitized G. gracilis) at a depth 
of 0-29 26 m and measured 86 mm body length 
(102 mm including the rostrum). The other 
parasitized G. ingens, a smaller female measur- 
ing 66 mm (82 mm including the rostrum), 
was taken at Station H52-15, the depth of cap- 
ture being unknown over a bottom depth of 
1207 m. In each case the parasite was attached 
to the middle of the ventral aspect of the first 
abdominal segment. Indeed, Fage describes this 
exact location as being constant among the 5 
parasitized individuals which he examined from 
the collections of the Dana. 
Nouvel (1941) also reports on 4 similarly 
parasitized individuals from the following three 
species of Gnathophausia : ( 1 ) G. ingens — 1 
parasitized specimen (a male of 110 mm meas- 
ured from the antennal scale to the end of the 
telson) from the eastern Atlantic off Mogador, 
Morocco, 0-4000 m; (2) G.gigas — 1 parasitized 
female of 115 mm from the Atlantic Ocean 
south of Spain, 0-4740 m; (3) G. zoea — 2 
parasitized females of 45 and 39 mm from two 
locations in the eastern Atlantic off Portugal, 
one at 1241 m, the other at 0-1500 m. 
Fage pointed out that the plate of fixation of 
this parasite is located just under the first ab- 
dominal nerve ganglion; and he observed a 
reaction of the host in the form of a great 
hypertrophy of this first abdominal ganglion as 
compared with the other abdominal and tho- 
racic ganglia and with ganglia in normal, non- 
parasitized individuals. 
Another influence of the parasite upon in- 
fected females is a retarded development of 
the secondary sexual characteristics, particu- 
larly the oostegites, which were considerably 
smaller and less well developed in the parasit- 
ized females than in non-infected females of 
the same size and presumably, of the same age. 
In addition, Nouvel describes an effect on the 
male G. ingens. In this male the sexual orifice 
is at the base of the last thoracic appendages. 
In addition this specimen has some very small 
outlines of oostegites at the bases of all the 
thoracic appendages except the last pair. This 
has been described as a "feminizing action” 
which the parasite exercises on the host. 
In the 2 parasitized females of G. ingens 
from the Scripps collections, a retarded devel- 
opment in the oostegites was noted as compared 
with the normal, non-parasitized females. In 
both the 66 mm specimen and the 86 mm 
specimen the oostegites were extremely minute, 
less than 1 mm in length. A normal female of 
only 70 mm was found to have oostegites 2 mm 
in length, and a non-parasitized female of 80 
mm possessed oostegites measuring 3 mm. 
However, in the case of the parasitized G. 
gracilis of 65 mm which I examined, the ooste- 
gites measured 4 mm in length and 1 mm in 
width. These measurements are similar to those 
for normal, non-parasitized females of this spe- 
cies of approximately the same length. Thus 
the parasite does not seem to have retarded the 
development of the oostegites in this parasit- 
ized G. gracilis , in contrast to its effects on the 
other species of Gnathophausia. 
