16 Messrs. J. Wood-Mason and A. xVlcock on II. — Natural Histori/ Notes from H.M. Indian Marine Survey Steamer ' Investigator^'' Commander R. F. Hoshyn, E.N., commanding. — Series II., No. 1. On the Results of Deep-sea Dredging during the Season 1890-91. By J. Wood-Mason, Superintendent of tlie Indian Museum, and Professor of Comparative Anatomy in the Medical College of Bengal, and A. Alcock, M.B., Surgeon I. M.S., Sur-geon-Naturalist to the Survey. [Plates VII. k VIII.] On the 18tli October, 1890, the ' Investigator ' left Bombay for the Andaman Islands, and on the 9th December following she crossed from the Andaman Islands to the Madras coast, reaching Bimlipatam on the 26th December. During these passages fifteen hauls of the trawl were taken in depths ranging from 95 to 1997 fathoms, and numerous deep-sea soundings were made. Between Bombay and Colombo, in the Laccadive Sea, numerous soundings were taken and four very successful trawlings were carried out. In this sea the bottom ai)pears to be mainly green mud, with a small percentage of Forami-nifera shells : in the immediate neighbourhood of the Lacca-dive Islands there is, of course, a great deal of fine coral detritus. The feature of these hauls were the starfishes, which will be duly noticed in the sequel. Between Colombo and the Andamans three successful hauls of the trawl besides many soundings were taken. The deep open part of the Bay of Bengal here worked over shows a bottom of Glohigerina-oozQ with numerous water-v/orn fragments of pumice ; but as one proceeds north-eastwards stiff blue mud is met with. The two deep hauls on this course gave a fine lot of starfishes and Holothurians. The third haul (Station 112), in 561 fathoms, must be particu-larly noticed. The trawl-bag came up crammed with mud of a low temperature, in which tlie specimens were imbedded. It may be surmised that compression under a great weight of cold mud kept up an approximation to normal bathybial con-ditions of temperature and pressure, in order to account for the fact that many of the crustaceans taken were found to be alive. Among these three species of Macrurous Decapods — Arista!us, s\). n., Ileterocarpus Alphonsi, Sp. Bate, and Wille-moesia forceps, A. M.-Edw. — were discovered to be luminous. In the case of Ileterocarpus Alphonsi clouds of a pale blue highly luminous substance, which not only illuminated tlie
Natural history notes from H.M. Indian Marine Survey steamer Investigator, Commander R.F. Hoskyn, R.N., commanding. Series II. No 1. On the results of deep sea dredging during the season 1890-91
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