COOKE : DISTRIBUTION OF PURPURA LAPILLUS. 193 



placed in the Leyden ITuseiim, and have since, I am assured by 

 Dr. J. Vernhout, been unfortunately lost. It was not brought from 

 the northern part of Novaya Zemlya in the collections made by 

 Ivanolf (Dautzenberg 24), nor by the Mission Benard in 1908 

 (Dautzenberg & Fischer 26), this latter expedition being mainly 

 concerned with dredging work. Nor was it found by the Isbjorn 

 in 1879, which dredged in very shallow water, but did no shore 

 collecting (Smith 109(f). The Belgica (Dautzenberg & Fischer 25) 

 went through the Matotschin Schar in 1907, but did not stay to do 

 any sliore collecting, and the Vega Expedition of 1875-6 (Leche 65) 

 dredged near the straits, but did not pass through them. The 

 Djwnphna (Collin 17) in 1882-3 visited several points in South- 

 West Novaya Zemlya, but does not seem to have done any shore 

 collecting. 



Middendorff (82) states that he brought home specimens of 

 P. lapillus from the White Sea, and is confirmed by Herzenstein (43), 

 a much later authority. On the other hand. Professor N. Nasonov, 

 the Director of the Zoological Museum, Imperial Academy of Sciences, 

 St. Petersburg, writing to me, quotes the view of Dr. Knipovitsch : 

 " Selon son opinion, \a Purpura lapillus uq se rencontre nullement . . . 

 dans la Mer Blanche meme." Both views are possible. The northern 

 limits of the White Sea are defined by Herzenstein (43) by a line 

 drawn from Cape Kanin in the east to Swyatoi Noss (or Holy 

 Cape) in the west. Within this line falls the most easterly point on 

 the mainland of Northern Europe and Asia on which P. lapillus has 

 hitherto been found, ^ viz. Trechoslrow or Tri Ostrova (Three Islands), 

 in 67° N. 40° E., near the mouth of the Ponoi River. On the other 

 hand, it is quite possible to define the White Sea proper by a line 

 drawn much further south, in the naiTow neck, in which case Tri 

 Ostrova falls outside the limits of the White Sea. Knipovitsch, in 

 his memoir on the fauna of the Solovetsky Islands (57), does not 

 mention P. lapillus. 



The fact that P. lapillus occurs on the west coast of Novaya Zemlya, 

 in 73° 20' N., and not in the interior of the White Sea, the main 

 body of which lies between 66° N. and 64° N., well to the south of 

 tlie Arctic Circle, is due to obvious causes. The water on the west 

 coast of Novaya Zemlya is no doubt affected by the flow of the Gulf 

 Stream past the northern coast of Norway, which raises its temperature 

 to about 40° F. in the month of August. The White Sea is un- 

 influenced by any current of warm water; it is beset with ice for 

 many months of the j^ear, and its temperature, both at the surface, 

 and at depths of 10, 40, and 75 fathoms, is known to be remarkably 

 low (Herzenstein 43). Novaya Zemlya acts as an effectual barrier to 

 the eastward advancement of any warm current, and the fauna of the 

 Kara Sea, and no doubt of the eastern coast of Novaya Zemlya itself, 

 is of an Arctic type. 



^ My authority is a letter from Professor Nasonov : " Le feu M. Herzenstein 

 n'a rencontre cette forme qu'a Tri-Ostrova, c'est a dire a I'entree-meme de 

 la Mer Blanche." 



