644 EEPORT— 1902. 



12 feet below the surface ; if tliat from a greater depth or from the actual surface could 

 have been obtained, a much larger variety of fauna would have been secured. The 

 plankton obtained was very varied. Diatoms (Coscinodiscus, Biddulphia, &c.), 

 Foraminifera (Globigerina), minute Algae (Peridineae, Ceratium, &c.), Meduste, 

 Pteropods, Radiolaria, Crustacea (Erichthius, Stomatopods, Amphipo'ds, Cirripeds), 

 Salpaj, &c. 



By far the largest proportion of the ocean plankton secured consists of Copepoda, 

 a division of the Entoinostraca, and I devoted my examination mainly to this class. 

 The amount of plankton taken by tow-net at different places was very unequal, and 

 depended upon atmospheric conditions— light, heat, cold, calm, or tempest greatly 

 influenced it. From causes difficult to explain, the tow-net was sometimes almost 

 empty ; at other times it contained masses of one class of life, the other forms pro- 

 bably haying gone to a greater depth. Copepoda are the commonest, and the most 

 •widely distributed of all marine life, often constituting the entire mass taken by 

 the tow-net._ Many of the surface species are buoyed up by their internal oil- 

 globules, as in the Arctic Seas, where one species {Calanusfiymiarchieiis), hardly 

 one quarter inch long, of red colour, is said to form the sole food of the Greenland 

 •whale. Most of the bottles contained several thousands of animals, many of which 

 required to be dissected with finely pointed needles under the microscope for the 

 determination of their species. In the fourteen bottles taken in the Indian Ocean 

 I found sixty-four species of free swimming Copepoda, comprising twenty-seven 

 genera, many of which had not been previously known in the Indian Ocean, and 

 probably some new species not yet determined, As might he expected, they are 

 mostly free swimming non-parasitical forms belonging chiefly to the families 

 Caknidffi, PontellidEe, Cyclopidre, Corycseidte, and Sapphirinidaj. Swarms of one 

 species sometimes occur in a particular gathering. In this connection I may allude 

 to T/-!ic^o(/<'s;«n/wi«7/^A?^rt'i(?», a minute reddish-brown Alga mentioned in 'Darwin's 

 Voyage of the " Beagle," ' and common in the Ked Sea, which nearly fills one bottle 

 collected off the Ceylon pearl banks. When the Ceylon material comes to be 

 examined it may probably be found widely distributed. We shall have a fairly 

 complete record of the plankton taken from the entire route traversed when the 

 whole collection is examined. 



On the Cuttlefishes collected bij P7'ofessor Serdman. 

 By W. E. HovLE, M.A. 



5. On Deposits dredged by Professor Herdman in the Indian Ocean, 

 By J. LoMAS, A.R.C.S., F.G.S. 



The samples of sea bottom, about thirty in number, were collected mainly from 

 four districts round the coasts of Ceylon, S. of Ceylon about Point de Galle, the E. 

 coast at Trincomalee Bay, Palk Bay N. of Eamiserram and Adam's Bridge, and the 

 Gulf of Manaar. 



In Galle Bay, from depths of 6 to 8 fathoms, shells with sand were dredged. 

 Large drifted shells, such as Area, Anomia, Ostrea, Cucullsea, and Turritella, 

 mostly in a rotten condition, made up the bulk of the coarse material, along with 

 large barnacle valves and a few sharks' teeth. Encrustation of NuUipores, Ser- 

 pulffi, and Polyzoa covered the shells, and Cliona borings were common in those 

 shells composed of calcite, while aragonite forms were not affected. 



The finer material, obtained by sifting through a sieve with a mesh of 1 mm., 

 contained from 61 --il to 62-52 per cent, of carbonate of lime, and included small 

 Molluscs, echinoid spines, plates and anchors of Holothurids, spicules of Alcyonium 

 and Leptoclinum, as well as many Foraminifera, such as Heterostegina, Globige- 

 rina, Textularia, and Spiroloculina, fragments of Molluscs, Crisia, and Nullipores, 

 and as inorganic constituents kyanite, corundum, zircon, rutile, tourmaline, mica, 

 and quartz. A considerable amoimt of coal, in pieces up to | inch in diameter, 

 •well rolled, may be due to accidental causes. 



