of the Fishery Board for Scotland. 123 
Enhydrosoma is a smaller and more slender form than Z. cwrvatum ; the 
female antennules are apparently only four- instead of five- jointed, 
the third and fourth joints in Z. cwrvatum being in this species completely 
coalescent. The first pair of thoracic feet are also somewhat different in 
the two species, but a greater difference is observed in the structure of 
the female fifth pair ; in HZ. curvatum there is a distinct though small 
- secondary branch, but in the present species the branches, which are 
sub-equal, do not appear to be distinctly separated. 
Enhydrosoma minutum, T. Scott, sp.nov. PI. iii., fig. 25 ; pl. vi., figs. 1-5. 
Description of the Female.—This is a small but moderately stout 
species as shown by the drawing (fig. 1, pl. vi.). Its entire length, 
exclusive of antennules and tail sets, scarcely reaches to ‘4 m.m. (about 
gp of an inch). 
The antennules (fig. 2, pl. vi.) are composed of five joints, but the 
fourth is very small; the armature consists of a number of moderately 
stout sete, a few of them being plumose, and the end joint carries a stout 
terminal spine as shown by the figure. 
The mouth organs resemble generally those of H. gracile, but the 
second maxillipeds are comparatively rather stouter (fig. 3, pl. vi.). 
The first pair of thoracic feet, which appeared to be somewhat similar 
in structure to the first pair in Z. gracile, were accidentally damaged, so 
that a correct drawing of them could not be prepared. 
The second, third, and fourth pairs are all somewhat alike in structure 
(pl. iii., fig. 25; pl. vi., fig. 4), and their outer branches do not differ 
greatly from the outer branches of the feet similar to them in FZ. curvatum, 
but the inner branches are very small, they each consist of two joints, the 
first joint being much shorter than the other, while the end joint tapers 
towards the distal end, and carries a single elongated terminal seta. 
The fifth pair (fig. 5, pl. vi.) are broadly foliaceous and resemble those 
of EZ. gracile; but the secondary branches are more distinctly articulated 
to the basal joints, and the sete of the two joints appear to be stouter. 
The furcal joints are extremely short. The female appears to carry one 
ovisac with several moderately large ova, 
Habitat.—Aberdeen Bay, Station V., Nov. 12, 1901. One specimen 
only. 
Remarks. —Hnhydrosoma minutum differs from the species already 
described by the difference in the structure of the antennules, and by the 
form and armature of the inner branches of the second, third, and fourth 
pairs of feet. No male specimen has been observed. 
Enhydrosoma curvatum (Brady and Robertson). 
1875. Rhizothrix curvata, B. and R., Brit. Assoc. Rept., p. 197. 
1880. Hnhydrosoma curvatum, Brady, Mon. Brit. Copepoda, vol. 
ii., p. 98, pl. Ixxxi., figs. 12-15; pl. lxxxii., figs. 11-19. 
This also occurred in the gathering from the old quarry near Granton ; 
it is quite distinct from the two species, . gracile and E. minutum, 
just described ; the difference in the structure of the fifth thoracic feet 
would alone be sufficient to separate them ; it is, moreover, a somewhat 
larger species. There is a previous record of this species from the Forth 
district, but from a different part of the estuary,* as well as from other 
places around the Scottish coasts. 
* Highth Annual Report of the Fishery Board for Scotland, Part III., p. 319 (1890). 
