( 325 ) 



The specimen agrees with other species of' the genus Corallium 

 in the absence of the eurious "opera glass" shaped spicules and the 

 presence of spicules of the oetoradiate type only in the general 

 coenenchym. 



It differs from Corallium and agrees with many species referred 

 to the genus Pleurocorallium in having the branches arranged 

 principally in one plane and the zooids scattered irregularly on 

 one face or snrface of this plane. 



The autozooids are indicated by well-defined verrucae projeeting 

 about 1 — 5 m.ra. from the general surface of the coenenchym. These 

 verrucae are large as compared with other species being about 1 — 4 

 m.m. in diameter. The coenenchym is thin and the axis hard and 

 either not marked or very faintly marked in some places by longi- 

 tudinal striations. 



The base of the main stem of the specimen is 6 m.m. in diameter 

 and the primary branches are 4 — 5 m.m. in diameter. 



Some further particulars concerning the anatomy of the species 

 will be described with illustrations in a future publication. For the 

 present the diagnosis of the species given above is sufficiënt. Before 

 concluding this preliniinary note I have, with very great regret, to 

 record that on Sept. 22 nd a fire broke out in my laboratory and 

 some portions of the specimen were seriously burned and scor- 

 ched. Fortunately there is still a considerable fragment that appears 

 to be uninjured. 



Wiskunde. — De Heer Kluyver doet eene mededeelinc; over 



„Een vraagstuk van meetkundige loaarschijnlijkheid" . 



s 



Het volgende vraagstuk werd onlangs (Nature, 27 July) gesteld 

 door prof. Pearson. 



"A man starts from a point O, and walks / yards in a straight 

 line; he then turns through any angle whatever and walks another 

 l yards in a second straight line. He repeats this process n times. 

 I require the probability that after these n stretches he is at a distance 

 between r and r -\- dr from lus starting point O." l ) 



Ik vind, dat de algemeene oplossing van dit vraagstuk berust op 

 de theorie der functies van Bessel, in het bijzonder dat die oplossing 



l ) Sedert (Nature, 20 August) deelde prof. Pearson mede, dat de oplossing voor 

 zeer groote waarden van n reeds in beginsel voorkwam in eene verhandeling over 

 het geluid van Lord Rayleigh. 



