240 



Th. Mortensen. 



with rather great certainty that the North coast, from the tracts 

 examined by the Danmark Expedition to those examined by the 

 Nares Expedition, will not differ essentially in regard to its Echino- 

 derm-fauna from that of these two places. The zoogeographical rela- 

 tions of the Echinoderm-fauna of Greenland can thus be taken up 

 now for a more detailed discussion. 



The total number of species of Echinoderms brought home b}' 

 the Expedition is 26, viz. 2 Crinoids, 12 Asteroids, 8 Ophiuroids, 

 1 Echinoid and 3 Holothurians. They are the following; 



Crinoid ea. 



1. Heliometra glacialis (Leach) 



2. Hathrometra prolixa (Sladen) 



Asteroidea. 



3. Bathybiaster vexillifer (Wyv. 



Thomson.) 



4. PontasterteiuiispiimsÇDûh.Kor.) 



5. Ctenodiscus crispatiis (Retz.) 



6. Poraniomorpha tumida (Stuxb.) 



7. Cribrella sangiiinolenta (O. F. 



Müll.) 



8. Pteraster militaris (O. F. Müll.) 



9. — puluilliis M. Sars. 



10. Solaster glacialis Dan. Kor. 



11. — papposiis (L.) 



12. Pedicellaster palæocrystallus 



Sladen. 



13. Stichaster albulus (Stimps.) 



14. Asterias panopla Stuxb. 



О phi u roi de a. 



15. Ophiopleiira borealis Dan. Kor. 



16. Ophioglypha robusta (Ayr.) 



17. Ophiocten sericeiim (Forb.) 



18. Ophiopiis arcticus Ljungm. 



19. Amphiura Siindevalli (M. Tr.) 



20. Ophiacantha bidentata (Retz.) 



21. Ophioscolex glacialis (M. Tr.) 



22. Gorgonocephahis eucnemis 



(M. Tr.) 



Echinoidea. 



23. Strongylocentrotus drøbachien- 



sis (O. F. Müll.) 



H oloth urioidea. 



24. Myriotrochus Rinkii Stp. 



25. Ciicumaria frondosa (Gunn.) 



26. Phyllophorus pelliicidus. Var. 



Barthii (Troschel). 



It is unfortunate that no Echinoderm-larvæ have been caught 

 by the Expedition. Owing to the small number of species occur- 

 ring there it would have been possible to refer almost any larva 

 to its parent species, the more so, as several of the species might 

 be eliminated as having non-pelagic larvæ, which may be concluded 

 from the large size of their eggs, even if their development is not 

 known (e. g. Ctenodiscus crispatiis, Ophiacantha bidentata). That the 

 plankton samples collected do not contain any Echinoderm-larvæ is 

 by no means a proof that none of the Echinoderms occurring here 

 have pelagic larvæ. Thus Strongylocentrotus drøbachiensis is known 

 to have pelagic larvæ, and it may be supposed with rather great 

 certainty that also some of the Ophiurids have pelagic larvæ; some 

 of the Asteroids might well be supposed to have such also. 



