391 Part ITI.—Highteenth Aunual Report 
Remarks.—This copepod has a superficial resemblance to a small 
form, with six-jointed antennules, described by T. and A. Scott under the 
name of (1) Canthocamptus parvus.* Like that form, the copepod now 
described has the antennules six-jointed, and the inner branches of the 
second, third, and fourth pairs of thoracic feet two-jointed, but the 
proportional lengths of the joints of the antennules are different, and the 
caudal furca, which in Canthocamptus parvus are very short, are ip. the 
species now described as long as the anal segment. No males have been 
observed. 
Habitat.—Moray Firth ; obtained amougst some dredged material. 
Mesochru spinicauda, 'T. and A. Scott. 
1895. Mesochra spinicauda, VT. and A. Scott, Ann. and Mag. 
Nat. Hist. (6), vol. xv., p. 52, Pl. V., figs. 12-25. 
This was one of several curious species that were found in shore pools 
at Musselburgh, Firth of Forth; the pools occurred between tide marks, 
but nearer low water, and were surrounded on all sides by beds of 
mussels. J am now able to record the occurrence of the species in shore 
pools near Millport, Cumbrae; it was obtained in some gatherings 
collected by hand-net on May 6th, 1899. 
Tetragoniceps (?) malleolata, Brady. (Pl. XIV., figs. 9-17.) 
1880. Tetragoniceps malleolata, Brady, Mon. Brit. Copep., vol. 
ll. p. 66, Pl/LXXVIIL., figs: 1-11: 
In Vart II]. of the Tenth Annual Report of the Fishery Board for 
Scotland (1892), p. 252,r I recorded the occurrence of a species of 
copepod which had been obtained in the Firth of Forth off St. Monaus, 
and which I had ascribed to Tetragoniceps malleolata, G. S. Brady. I 
then pointed out, however, that this copepod, while agreeing in most 
points with the genus and species named, differed in so far as if 
possessed nine-jointed instead of eight-jointed antennules, and in the fifth 
pair of thoracic feet being two-jointed instead of being composed of only 
one joint. At the time the record was published, I was quite aware that 
the second of these two differences was, in view of the definition of the 
genus, a somewhat important one, but considered that, as the copepod 
referred to resembled the species named in almostall the other details of 
structure, it was better to ascribe it to that species rather than to 
institute a new genus or species for its reception. 
During the past year I have obtained, in some dredged material from 
the Firth of Forth collected in 1896, but only recently examined, a few 
more specimens of the copepod referred to above, as well as of another 
and somewhat closely allied form that appears to be undescribed. 
When the supposed Zetragoniceps malleolata was recorded in the 
Tenth Annual Report no detailed description of the form was given; a 
reference to the two principal points of difference was considered to be at 
that time all that was necessary for the identification of the form. The 
occurrence, however, of the closely allied and apparently undescribed 
species which I have alluded to makes it desirable that a description of both 
forms should now be given, so that the differences that have been observed 
between them may be more clearly indicated. 
It may be considered doubtful whether the two forms to be described 
should be retained in the genus Tetragoniceps, but for the present, at 
* Ann. and Mag. Nat. Hist. (6), vol. xviii., p. 6, Pl. IL., figs. 14-22 (1896). 
+ Additions to the Fauna of the Firth of Forth, Part IV. 
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