1898-1902. No. 13] ECHINODERMATA. 25 



(34, p. 95), it attains about the same size on the northern shores of 

 Norway, while on the west and south coast it is only about 40 mm. 

 MiCHAiLovsKij (26, p. 472) states the size of the species from Spitz- 

 bergen to be 80 mm. 



The specimens from Jones Sound and Rice Strait appear to have a 

 comparatively lower and more depressed shell than those from the west 

 coast of Greenland (Egedes Minde and Upernivik). In the latter, the 

 average proportion of the height of the test to its diameter was as 

 1 : 1.81, varying also between 1 : 1.65 and 1:2; while in specimens from 

 Jones Sound, the average proportion was as 1 : 1.97, and in those from 

 Rice Strait as 1 : 1.92. The proportion varied between 1 : 1.65 and 

 1 : 2.3. At Spitzbergen, this species appears to be still more depressed, 

 as, according to Michailovskij, the proportion of the height of the test 

 to its diameter varies between 1 : 1.9 and 1 : 2.5. 



The specimens from the south side of Jones Sound, North Devon, 

 are remarkable for their comparatively short (up to 11 mm.) robust 

 spines; while those from the north side, Havne Fjord and Gaase Fjord, 

 have very thin, slender spines, up to 20 mm. in length. In specimens 

 from Rice Strait, too, the spines were short and strong. The spines 

 are subject to great variations with regard to length and thickness, even 

 in specimens from the same locality. 



The number of pores varies between 4 and 7, 6 being the most 

 frequently occurring number. The colour varies between purple and 

 greyish green. 



Holoth urioidea. 



Myriotrochus rinki, Steenstrup. 



Locality. 

 Aug. 18, 1898. Bay in Rice Strait. 

 Aug. 24, 1898. — „ — „— 

 Aug. 26, 1898. — „ -„- 

 July 29, 1899. Winter harbour, Havne Fjord; 12 m. 

 July 22, 1899. - — — ; 16 m. 



July 30, 1900. Mouth of Stor Valley. 



Sept. 19, 1900. Off Forvisnings Valley; 49-4 m. Clay and small 

 stones. 



