December 9, 1915] 



NATURE 



411 



tiie Government of that province to investigate its 

 conditions in other parts of the country. 



Among the five areas in which the shells are col- 

 lected — 'linnevelly, usually known as the Tuticorin 

 fishery, Ramnad,' the Carnatic Coast, Travancore, and 

 Kathiawar— the first is the only place where it is 

 c urried on systematically, and it has existed here for 

 at least 1800 years. Early evidence of the use of the 

 >heU is found in the Foote collection of Indian pre- 

 liistoric antiquities in the Madras Ck)vernment 

 Museum, and more recent excavations, conducted by 

 Mr. A. Rca, have furnished additional examples. In 

 Mysore the specimens have been supposed to date 

 back to Neolithic times, but as the shells cannot be 

 worked without a metal saw, they probably belong to 

 a later ago, that of iron. 



In Tinnevelly, where the industry is carried on under 

 ofticial superintendence, about seventy divers are em- 

 l)loyed. In favourable circumstances, a diver may 

 in each excursion to the beds make twenty-five de- 

 scents, each yielding from nothing to eight shells. 

 Ihese on reaching the shore are classified in nine 

 i^rades, ranging from 4 to 2\ inches in diameter; 

 ihe wormed shells, being of inferior value, are placed 

 in a special category. 



The chief economical value of the shell is for the 

 production of bangles or bracelets, the object of wear- 

 ing them being partly for purposes of ornament, 

 ])artly as a protective against evil spirits and the 

 < vil 'eye. While the source of supply is mainly 

 southern India, the manufacture of bangles is now 

 j)ractically confined to Bengal. Mr. Hornell suggests 

 ihat this transference of the manufacture took place 

 in the fourteenth century, which marks the downfall 

 t Hindu supremacy in the south, when the rich cities 

 A the Pandyan kingdom were sacked by the 

 Alahomedans, and the coast trade passed into Arab 

 iiands. At the present day the shells are imported to 

 Calcutta, and pass thence to Dacca and other centres 

 in Bengal, where they are cut by the Sankhari caste, 

 which holds a high place in the Hindu social system. 

 The wearing of chank bangles is now virtually con- 

 fined to Lower Bengal and the hill tribes north and 

 rast of the province, from the Santals to the tribes 

 (if Assam and Manipur, and from the Sunderbuns to 

 the Himalayas and the Tibetan plateau. Some 

 2\ million shells appear to be worked up annually 

 in Bengal. The columella is first extracted by sawing 

 otY a slice of the lip and smashing the apex. The 

 sawyer sits on an earthen floor tightly wedged be- 

 tween two short wooden stakes driven into the ground, 

 one supporting his back and his toes against the 

 other. He presses with one foot a disc of hard wood 

 against the mouth aperture and divides the shell into 

 >.t'Ctions with a heavy saw, the blade of which is in 

 lie form of a crescent ending in a hook at each end. 

 I he use of any more elaborate machinery is unknown. 

 He is paid about one rupee for every ten shells he 

 ( uts. The work is very fatiguing, owing to the con- 

 strained position of the artificer. 



Besides being cut into bangles, the shell supplies 

 other forms of ornament, rings, necklaces, coat or 

 dress buttons being made from it. Up to quite recent 

 times these shells were used as currency in the Naga 

 Hills. Some of the fragments are burned into a fine 

 lime, used for industrial purposes and as a cure for 

 various diseases, such as rickets, asthma, and cough. 

 This is justified by modern medical research, the lime 

 being useful to strengthen the bones of rickety children 

 or by the deposit of salts round tuberculous centres. 

 A minor use of the shell is to supply the equivalent 

 of our infants' feeding-bottles. 



Besides these economical uses of the shell, it is 

 employed in various ways connected with the religious 



NO. 2406, VOL. 96] 



and social life of the Hindus. It is the emblem of 

 the god Vishnu, and when the convolutions take the 

 sinistral or left-hand form it is highly valued, and 

 deposited jn temples of the god. The four daily 

 services at a Hindu temple are announced by blowmg 

 the shell, which in ancient times was also used as a 

 war trumpet. No one who has encamped near a 

 Hindu temple will forget the weird muffled roar which 

 calls the god to wake at early dawn and receive the 

 service of his worshippers. Beggars blow the shell as 

 an appeal for alms. It is specially valued as a pro- 

 tective against the evil eye, and hence water is poured 

 from it on the foundation-stone of a temple or house, 

 or it is hung round the necks of children or cattle. It 

 is blown at harvest when a man undergoes a special 

 purification and is sent to cut the first-fruits, and at 

 marriages to scare the evil spirits which beset bride 

 and bridegroom. With the same object it is sounded 

 when a corpse is being carried to the funeral pyre or 

 to the burial ground. 



On the whole, this survey of one of the purely 

 indigenous industries of the countr}', the products of 

 which are all locally absorbed, is of sufficient interest 

 to justifv the labour which Mr. Hornell has under- 

 taken in collecting the materials for his excellent 

 monograph. 



LUMINOUS INSECTS.^ 



THE power of emitting light at night is a property 

 that has been developed to varying extent in 

 many different branches of the animal kingdom. We 

 find it, for instance, in the Protozoa, e.g. Noctiluca, 

 an organism which, though microscopic in size, is 

 sometimes present in such countless millions on the 

 surface waters of the ocean as to make the whole sea 

 appear to be ablaze with a pale, cold, "phosphor- 

 escent" light. Higher in the animal scale we find the 

 property well developed in the Hydrozoa, e.g. Pyrp- 

 soma, a colonial oceanic form. We have it again in 

 numerous molluscs, in the insects, and even in the 

 vertebrates, a large number of the fish that inhabit 

 the abysmal depths of ocean, where the sun[s rays 

 can never penetrate, carrying their own lamps disposed 

 about their bodies in patterns that vary according to 

 the species. Here, however, I propose to consider 

 onlv the insects that exhibit this power. 



There is, as might be expected considering the strik- 

 ing nature of the phenomena in question, a very ex- 

 tensive literature on the subject. This is for the most 

 part scattered throughout numerous scientific period- 

 icals, but the earliest part of it, up to 1887, has been 

 collected together by Gadeau de Kerville in his "In- 

 sects Phosphorescents," published in that year. 



It is rather remarkable that the beetles (Coleoptera) 

 have almost a monopoly of light emission amongst 

 insects, and even here the property is almost confined 

 to two families. The first, and by far the most im- 

 portant of these, for our consideration, is the Lam- 

 pyridze, or, to give them their popular name, the 

 glow-worms and fireflies. With them are associated 

 one or two small closely allied families, the Phengo- 

 didee, Rhagophthalmidae, etc., some of which are as 

 yet very imperfectly known and unsatisfactorily char- 

 acterised. In the ' Lampyridae proper the luminous 

 organs, when present, are generally found in both 

 sexes, though frequently more strongly develoijed in 

 one than in the other, and are situated in the terminal 

 or subterminal segments of the abdomen, the light 

 being shown from the ventral surface. 



All members of this society are familiar with the 

 glow-worm of this country, Lampyris noctiluca. I 



1 From a paper rend before the South London Entomological and Natural 

 History Society by K. O. Blair. 



