1904 - 5 .] The Pelagic Fauna of the Firth of Clyde. 783 
stituent of the plankton during the winter and spring, were 
less conspicuous during the summer, owing to the appearance of 
other animals. They occurred, however, in nearly every haul of 
the tow-net, but Paracalanus occasionally took a long leave of 
absence. 
The three summer months — June, July and August — were 
the best and richest months for plankton in the Clyde. The 
characteristic feature of the summer was the vast quantity of 
Diatoms, which frequently became a nuisance, as they quickly 
clogged up the meshes of the tow-net, and thus reduced its 
catching capacity. Amongst the forms which occurred during 
the summer, I may specially mention Eupliysa aurata, Evadne 
nordmanni , and Cyphonautes towards the end of August. 
During the autumn months the predominant species were 
Pseudocalanus elongatus, Acartia clausi , Oikopleura dioica , and 
Sagitta bipunctata for a short period in November. 
COELENTEBA. 
Hydromedusae and Scyphomedusae. 
(See Keport by Browne on pages 738-778.) 
SlPHONOPHORA. 
Cupulita sarsii, Haeckel, 1888. 
Cupulita sarsii , Browne, 1900, p. 678. 
Two isolated nectocalyces were taken on 15th November 1902. 
They were probably the swimming bells of Cupulita sarsii. This 
siphonophore is common on the west coast of Ireland, and has also 
been occasionally taken in the Irish Sea. 
Anthozoa. 
Arachnactis bournei, Fowler, 1897, p. 805. 
A single specimen taken on 8th May 1901. This larval stage 
is not uncommon during the spring and summer at Plymouth 
