300 
Part III, — Ninth Annual Report 
v.— ADDITIONS TO THE FAUNA OF THE FIRTH OF FOETH. 
Part III. By Thomas Scott, F.L.S. 
Forty-two species of Crustacea and one species of Mollusca are in this 
paper recorded for the Firth of Forth. Though several groups of the 
Crustacea are represented among those now recorded, by far the greater 
part belong to the Copepoda^ of which there are 31 species, while the 
Ostracoda^ Cladocera, AmpMpoda, Isopoda, and Schizopoda are each 
represented by 1 species, and the Decapoda by 3. 
It will be observed from this and previous papers that the Firth of 
Forth possesses a rich crustacean fauiia. Previous to 1887 about 120 
species had been recorded for the Forth ; whereas now there are, including 
those mentioned in the present paper, about 370 species, besides several 
which are still undetermined. But though the number of species has 
within recent years been considerably increased, I do not think it can yet 
be considered as approximately representative of the crustacean fauna of 
our estuary; and I venture to predict that when the Firth of Forth 
becomes more thoroughly and systematically worked up the number of 
Crustacea will be little, if at all, short of 500 species. 
COPEPODA. 
GNATHOSTOMA. 
CALANIDiE. 
Metridia armata^ Boeck. 
1865. Metridia armata, Boeck, 'Oversigt over de ved Norges 
Kyster iagttagne Copepoder,' p. 14. 
1873. Paracalanus hibernicus^ Brady and Robertson, 'Ann. and 
Mag. Nat. Hist.,' ser. 4, vol. xii. p. 126, pi. viii. figs. 1-3. 
1878. Metridia armata, Brady, 'Mon. Brit. Copep.,' vol. i. p. 42, 
pi. ii. figs. 1-12; pi. Ivi. figs. 19, 20. 
Habitat — In various parts of the Forth, between Inchkeith and May 
Island, I have obtained this species several times during the past year 
with both the surface and bottom tow-nets, but not very common. It is 
readily distinguished, especially the female form, by the elongated joints 
of the abdomen, and several of the first joints of the anterior antenna 
being strongly toothed on the upper edge. 
Acartia discaudatus, Giesbrecht. 
1881. Dias discaudatus, Giesbrecht,"^ 'Die Freilebenden Cope- 
poden der Kieler Foehrde,' p. 148, pi. iii. figs. 4, 22, 23; 
pi. V. fig. 18; and other plates. 
Habitat. — Between Portobello and Cockenzie, well inshore. I obtained 
several specimens of this species ; the peculiar form of the caudal furca 
first attracted my attention. In the female the last abdominal segment is 
much broader posteriorly ; the furca are broad flattened plates, which 
together are in breadth about equal to the length of the furca and last 
abdominal segment. This appears to be the first British record of Acartia 
discaudatus. 
* Vierter Bericht der Commission zur \oissenschaftUchen Untersuchung der deutschen 
Meere, in Kiel, 1887-1881. 
