■417 Notes on the Natural llistorij of East Finmarh. 



witli others in my collection from Greenland ; the number of 

 spokes in the Fiumark specimens ranges from sixteen to 

 twenty-one. 



Genus Trociiodehma, Thecl. 



Trochoderma elegans, Theel. 



1877. Trochoderma eler/ans, Theel, " (^uelques Holotliuries des Mers de 

 la Nouvelle Zemble," Nov. Acta Reg-. Soc. Sc. Up3ala, ser. iii. p. 11 

 (separate copy), pi. ii. 



This genus, like the last, is furnished with wheel-like 

 spicules, but the tyre is rounded and armed with spines 

 instead of furnished with triangular inward-directed processes, 

 as in Myriotrochus. 



Ostergren writes : — " I have now before me a specimen of 

 this species which is new to the Norwegian fauna ; it was 

 obtained by G. O. Sars at Mortensnes, in the Varanger 

 Fiord'' C^ Holothuroidea of Northern Norway," Bergens 

 Mus. Aarbog, 1902, p. 21). 



EXPLANATION OF PLATE XXMI. 



Fig. 1. Eupi/rr/7i!^ scabcr, Liitkeii, magnified ; tlie actual length indicated 



by the line below. 

 Fiff. 2. The same. Spicules as seen from above. 

 Fi//. 3. The same. Spicules as seen from the side. 

 Fiff. 4, C'ldrodota Icsvis, Fabricius. A spicule. 

 Fiff. 5. Myriotrochus jRinkii, Steeustrup. Wheel-spicule in early stage 



of development. 

 Fig. 6. The same. Wheel-spicule seen from "above. 

 Fig. 7. The same. Wheol-spicule seen from below. 

 Fig. 8. The same. AVheel-spicule seen obliquely. 

 Fig, 1). The same. Wheel-spicule seen from the side. 



