Report Oll the Ecliinoderms of North-East Greenland. 287 



hole is formed; but the 3 original holes are always more or less 

 easily recognizable. The spire consists of 3 rods, generally completely 

 coalesced, slightly tapering and quite smooth (Fig. 6 c, d); in a few 

 cases a small hole was found at its base. Among these plates are 

 found, in rather great number, different stages of development 

 (Fig. 6e — g). The size of the plates is ca. 02— 03 mm, the spire 

 measuring ca. 017 mm. The supporting rods of the caudal appen- 

 dage (Fig. 7) generally have 3 — 4 holes in the enlarged middle part, 

 and generally a small, simple spire, consisting of three more or less 

 completely coalesced rods; the spire may be slightly spinous. 



Zoogeographical remarks on the Echinoderm- 

 fauna of Greenland. 



The first author to treat the zoogeography of the Echinoderms 

 of Greenland was Lut ken, who in his "Oversigt over Grønlands 

 Echinodermata" 1857 gave a very careful study of this matter. It 

 was a necessary consequence of the fact, that at that time the 

 knowledge of the distribution of these animals was rather insuffici- 

 ent, that the results could not be very satisfactory. But the available 

 material was, indeed, used in an excellent way. The Greenland 

 fauna was compared with the neighbouring faunas, especially with 

 that of North America and Scandinavia, while for want of knowledge 

 that of the Siberian Ice Sea and the North Pacific could not be taken 

 into account. It was tried to distinguish between the arctic and the 

 boreal species — that the results do not always agree with our pre- 

 sent view's hereof, likewise depends on the insufficient knowledge at 

 that time of both the distribution of the species and of the oceano- 

 graphy and hydrography of the northern Seas. The boundary 

 between the arctic and subarctic region was sought, not in the 

 Polar circle — as is done so much later in the '"Fauna arctica" — 

 but (in accordance with Dana) in the temperature, the "Isocrymal- 

 line" Г7°С. being taken as the limit, so that the Arctic region in 

 the map accompanying the work nearly coincides with the region 

 as it is now understood (cf. "Ingolf" Echinoidea. II. p. 179). — Upon 

 the whole the question of the zoogeography of the northern Echino- 

 derms could, at that time, scarcely have been better treated. — 



Since Lütken published his study nobody has treated the zoo- 

 geography of the Echinoderms of Greenland specially; but through 

 the works of more recent years: the "Ingolf" Expedition and the 

 several expeditions to Greenland, last but not least the "Tjalfe" Expe- 

 dition, further through the researches especially of D öd er lein, 



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