T etraplatia — Hand 
341 
recorded to the surface and the number of 
specimens captured and depths reached were 
as follows: 
Depth 
510 
620 
775 
846 
870 
890 
960 
995 
1,005 
1,022 
1,065 
Number of Specimens 
1 
2 
1 
3 
2 
2 
4 {Vi of sample only) 
2 
7 
19 
1 
Tetraplatia, like most medusans, seems to 
be a rather omnivorous carnivore. Dantan 
(1925) seems to be the only other worker 
who has noted any of the food items of these 
animals and he found only a few specimens 
containing any identifiable food substances. 
He found the remains of an annelid larva, 
parts of a crustacean and a small chaetognath. 
In the specimens from the Pacific, also, only 
a few individuals have been noted containing 
identifiable food items. These included an 
immature euphausiid, a chaetognath and 
three copepods. Two specimens of Tetraplatia 
were noted whose mouths were widely flared, 
Fig. 7. A sketch of Tetraplatia volitans which had 
captured a chaetognath. 
as if they had been attached to some rather 
large animal at the time of capture. An or- 
ganism such as Tetraplatia can readily ingest 
another animal of its own bulk which was 
nearly the situation with the specimen found 
ingesting the chaetognath. This individual 
with the partly swallowed arrow worm is 
sketched in Figure 7. 
Nematocysts 
Recently considerable attention has been 
turned toward the nematocysts of coelen- 
terates. Weill (1934) used these structures to 
show phylogenetic relationships and Papen- 
C 
Fig. 8. Nematocysts of Tetraplatia volitans: a , a large 
atrich; b and c, small atrichs. 
fuss (1936) and Hand (1954) have shown 
that these characters may be useful in the 
identification and separation of species. 
Russell (1938, p. 162) concurs with Weill 
that the study of nematocysts "may be of 
value in showing phylogenetic relationships," 
but questions their value as specific characters. 
In his elaborate study of 1934, Weill con- 
sidered the nematocysts and affinities of Tet- 
raplatia volitans and concluded that these 
animals were narcomedusans. He did not per- 
sonally observe the nematocysts of this spe- 
cies but instead based his conclusions on the 
descriptions and figures of Viguier (1890). 
