620 



NA TURE 



[April 30, 1903 



been comparatively short, both stations have suffered from 

 " mikroseismische Unruhe " (air tremors?). 



At the present moment the most interesting station where 

 world shaking earthquakes are recorded is at Pribram 

 where on the surface and at a depth of noo m. Wiechert's 

 pendulums are installed. From the few records hitherto 

 obtained, it appears that the motion on the surface and that 

 underground have a striking similarity. 



D 



DR. GOELDI ON BRAZILIAN DEER. 

 H. E. GOELD] has decidedly advanced our knowledge 

 of the deer of South America by a memoir on the ant- 

 lers of three Brazilian species recentlv published in the 

 Memonas of the museum at Para of which he has charge 

 {Mem. Mus. Goeldi, part Hi., 1902). All South American 

 deer, it need scarcely be said, differ markedly from the more 

 typical deer of the Old World, the males of the larger 

 species, together with their relatives, the white-tailed and 

 the mule deer of North America, being specially distin- 

 guished by the form of their antlers, which branch in a 

 fork-like manner some distance above their base instead 

 of giving off a brow-tine close to the latter. Hitherto 

 naturalists, in Europe at any rate, have had no definite 

 information with regard to the gradual increase in the com- 

 plexity of the antlers of the South American species as thev 

 are annually renewed. This deficiency in our knowledge has 

 been supplied in the case of the marsh-deer, the pampaf-deer 

 and the one commonly called Cariacus gymnotis, in the 

 memoir before us. With great pains, Dr. Goeldi has col- 

 lected a large series of the antlers of each of the three 

 species belonging to animals of different ages, and in the 

 plates accompanying his memoir has figured a selection 

 which serves to display the gradual evolution from the voung 

 to the adult form. In the course of the memoir' it is 

 incidentally mentioned that the aforesaid C. gymnotis 

 which ,s a near relative of the North American whitetail' 

 has only recently made its appearance in Brazil, its proper 

 home being Colombia and Guiana. 



THE PEARL FISHERIES OF CEYLON.* 

 'pHE celebrated pearl "oysters" of Cevlon are found 

 mainly in certain parts of the wide shallow plateau 

 which occupies the upper end of the Gulf of Manaar off the 

 north-west coast of the island and south of Adam's Bridge 



The animal (Margaritifera vulgaris, Schum. = Avicula 

 fucata Gould) is not a true oyster, but belongs to the family 



Wicuhda 1 and is therefore more nearly ■ related to the 

 mussels (Mytilus) than to the oysters (Ostra-a) of our seas 



I he fisheries are of very great antiquity. Thev are re- 

 ferred to by various classical authors, and Pliny speaks of 



he pearls from Taprobane (Ceylon) as " bv far ?he bes 

 in the world. Cleopatra is said to have obtained pearls 



rom Anpu, a small village on the Gulf of Manaar, which 

 .- si, I the centre of the pearl industry. Coming to more 

 recent times, but still some centuries back, we have records 

 of fisheries under the Singhalese kings of Kandy and sub! 

 sequently under the successive European rulers-1 he Portu 

 fhTn tTI '" Pr ession from about ,c«k to about i6„ 



he Dutch from that time to about i 79S , and the English 



rom the end of the eighteenth century onwards. A notable 

 feature of these fisheries under all administrations has been 

 their uncertainty. 



The Dutch records show that there were no fisheries 

 be ween , 732 and 1746, and again between 1768 and ',, 



finin f V 54, c l8b4 and several succeeding years and 



his work was completed) in tSct tr, ,a "'■ a,ea before 



Holdsworth in , 86,-10 iSfio h I '^ c| ' and ,hat "' Mr. 

 much practical result so rS' "" ^ ^ertaken without 



byp™;. wf A°f H^dSTrST" 1 " ' he R ° yal InS ' i,utio " - M«* *7 



NO. 1748, VOL. 67] 



In September, 1901, I was asked to examine the records 

 and report on the matter, and in the following spring was 

 invited by the Government to go to Ceylon with a scientific 

 assistant, and undertake what investigation into the con- 

 dition of the banks might be considered necessary. Arriving 

 at Colombo in January, 1902, as soon as a steamer could 

 be obtained we proceeded to the pearl banks. In April it 

 was necessary to return to my university duties in Liver- 

 pool, but I was fortunate in having taken out with me as 

 my assistant Mr. James Hornell, who was to remain in 

 Ceylon for at least a year longer, in order to carry out the 

 observations and experiments we had arranged, and com- 

 plete our work. This programme has been carried out, and 

 Mr Hornell has kept me supplied with weekly reports and 

 with specimens requiring detailed examination. 



ihe s.s. Lady Havelock was placed by the Cevlon Govern- 

 ment at my disposal for the work of examining into the 

 biological conditions surrounding the pearl oyster banks- 

 and this enabled us on two successive cruises of three or 

 lour weeks each to examine all the principal banks and 

 run lines of dredging and trawling and other observations 

 across, around and between them, in order to ascertain the 

 conditions that determine an oyster bed. Towards the end 

 of the time I took part in the annual inspection of the pearl 

 banks, by means of divers, along with the retirin- in- 

 spector, Captain J. Donnan, C.M.G., and his successor 

 Captain Legge. During that period we lived and worked 

 on the native barque Rangasameeporawee, and had daily 

 opportunity of studying the methods of the native diver's 

 and the results they obtained. [These were discussed in 

 the lecture and illustrated by lantern slides.] 



It is evident that there are two distinct questions that 

 may be raised— the first as to the abundance of the adult 

 oysters, and the second as to the number of pearls in 

 the oysters— and it was the first of these rather than the 

 frequency of the pearls that seemed to call for investi- 

 gation since the complaint has not been as to the number 

 of pearls per adult oyster, but as to the complete disappear- 

 ance of the shell-fish. rr 



Most of the pearl oyster banks or " Paars " (meaning 

 rock or any form of hard bottom, in distinction to " Manul " 

 which indicates loose or soft sand) are in depths of from' c; 

 to 10 fathoms, and occupy the wide shallow area of nearlv 

 50 miles in length, and extending opposite Aripu to 20 miles 

 in breadth, which lies to the south of Adam's Bridge On 

 the western edge of this area there is a steep declivity the 

 sea deepening within a few miles from under I0 to more 



IZ? '<°?u r T S t : xV hMe ° Ut in the centre of the southern 

 part of the Gulf of Manaar, to the west of the Chilaw Pearl 

 Banks, depths of between one and two thousand fathoms 

 are reached. On our two cruises in the Lady Havelock we 

 made a careful examination of the ground in several places 

 outside the banks to the westward, on the chance of find- 

 ing beds of adult oysters from which possibly the spat de- 

 posited on the inshore banks might be derived. No such 

 beds, outside the_ known "Paars," were found; nor are 

 they likely to exist. The bottom deposits in the ocean 

 abysses to the west of Ceylon are entirely different in nature 

 and origin from the coarse terrigenous sand, often cemented 

 into masses and the various calcareous neritic deposits 

 such as corals and nullipores, found in the shallow water 

 on the banks. The steepest part of the slope, from ,o or 

 20 fathoms down to about 100 fathoms or more all alonsr 

 he western coast seems in most places to have a hard 



nd o,he° r Ve ? W ' th Ak '- TOnaria . s Ponges, deep-sea corals 

 and other large encrusting and dendritic organisms 



diff did ™ f !? Pe ""a 1 " the deep water be ™ nd *« 

 clifl did we find any ground suitable for the pearl oyster to 

 live upon. r • 



Close to the top of the steep slope, about 20 miles from 



™ cf Vn - P P S ° f '""u 8 t0 I0 fath0mS is situated 'he 

 largest of the Paars," the celebrated Periya Paar which 



has frequently figured in the inspectors' reports, has often 



fauseY'd 6 t0 H° PeS ° f gre3t fisherieS ' and "as as o ten 

 Zids X d,Sa PP°' ntme nt to successive Government 



north and so,,r h enya ?"* ■""^ ab ° Ut » "^tical miles 

 I If? 5 1 • and vanes from one to two miles in 

 breadth, and this-for a paar-large extent of ground be- 



vTTmTsfinf I™"*™* >'°"ng oysters, which how- 

 tion This ,marlab, - v disappear before the next inspec- 

 tion. This paar has been called by the natives the " mother- 



