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 



