638 REPORT — 1889. 



TUESDAY, SEPTEMBER 11. \ 



The following Papers were read : — 



Zoological Department. 



1. On the Bestoration of Astei-olepis maximus (Agassiz), with remarhs on the 

 Zoological Affinities of the Pterichthyidm. By Dr. E. H. Traquair, F.E.S. 



2. On some new and rare Copepoda recently found in Liverpool Bay. 

 By Isaac C. Thompson, F.L.8., F.B.M.S. 



The paper may he taken as supplementary to one read by the author at the 

 Manchester meeting- of the Association in 1887, in which several species of Copepoda 

 new to Britain were referred to. The investigation of this class of microscopical 

 Crustacea has heen actively continued in connection with the scheme of the 

 Liverpool Marine Biology Committee (L. M. B. C), instituted by Professor 

 Herdman five years ago for investigating the fauna of Liverpool Bay, and of whose 

 researches a second volume has recently been published. 



Ninety-four marine species of Copepoda have already been found in the district, 

 the present paper referring especially to eleven of these which are new to Britain, 

 four being new to science. 



The latter are Cymbasoma Herdmani, Hersiliodes puffini, Jonesiella hyence, 

 and Lichomolgus sabella, and have been or will be fully described in the ' Proceedings 

 of the Liverpool Biological Society.' The others new to Britain not referred to in 

 the previous paper are Paracalanus parvus, Claus, Pontella Kroyeri, Brady, Giardella 

 eallianassce, Canu, Lichomolgus albens, Thorell, Cymbasoma rigidum, Thompson, 

 Lemma branchialis, Linn, and Artotrogus orbicularis, Boeck. 



The establishment of the biological station on Puffin Island at the entrance to 

 the Menai Straits has proved of immense benefit in the investigation of marine 

 fauna, most of the above species, as well as many other rare ones new to the district 

 having been there taken by tow-net, or in the numerous tidal rock-pools, mud 

 deposits, or parasitic on other animals. 



By the use of the electric light while cruising in the steamer ' Hyaena,' belonging 

 to the Liverpool Salvage Association, many valuable species of Copepoda and other 

 free-swimming Crustacea have been taken. The modus operandi has been described 

 by Professor Herdman (' Nature,' May 9, 1889), and includes the brilliant illumina- 

 tion of the surface of the sea, that portion being meanwhile skimmed by tow-nets, 

 and also the illumination at the sea-bottom and intermediate depths by means of 

 submarine incandescent lamps of fifty-candle power fitted into the mouths of finely- 

 meshed tow-nets. The Copepoda thus taken by the deep tow-nets included num- 

 bers of the genus Harpaeticus of remarkably large size, and the theory seems 

 tenable that they, being well known as foul feeders, mistook the electric light for 

 the phosphorescent glow of decomposing animal matter. 



The results obtained from the brilliant surface illumination were very striking. 

 The examination of the Copepoda obtained by slowly dragging a surface tow-net 

 over the illuminated portions of the sea round the vessel, yielded twenty separate 

 species in one haul. They include some very rare ones, notably Pseudocalanus 

 armatus, Boeck, which has not before been recorded in Great Britain except at 

 great depths in the Clyde. Amongst the other uncommon forms were Ectinosoma 

 atlanticum, Zaus spinatus, Laophonte lamellifera, Dactylopus tenuiremis, D. 

 tisboides, Cyclopina gracilis, Bradyn typica, and Euterpe gracilis. With them was 

 a perfect shoal of Peltidimn depresmm, a species usually confined to the fronds of 

 Laminaria, and attached to other Algae. It is evident that the electric light is 

 able to draw these minute Crustacea from their secret hiding-places in a remarkable 

 manner, and considerable further results are anticipated from this source. The 

 paper deals with the geographical distribution of Copepoda and their gregarious 

 habits, and their prevalence as affected by commerce and the drainage of large cities. 



