I30 DISCOVERY REPORTS 



of the Antarctic is related to that of the extreme south of South America. The Phrixo- 

 metra, of which the Discovery vessels took five specimens, one at South Georgia and 

 four in the Bransfield Strait, is so like Carpenter's Phrixometra longipinna from off the 

 River Plate that I have described it as a variety. The only other species of the genus are 

 P. nutrix, and P. rayneri from the Shag Rocks. 



There are four species of Isometra in the Antarctic, one of which also occurs on the 

 east coast of South America. Two other species are known, each described from a single 

 Challenger specimen taken off the River Plate. 



These facts point to a relationship between the shallow-water crinoid faunas of the 

 Antarctic and of the east coast of the extreme south of South America. There appears 

 to be a relationship with the west coast of South America too. 



Of the four genera of the Heliometrinae represented in the Antarctic three, Pro- 

 machocrinus, Anthometra and Solanometra, are monotypic and the species are confined 

 to the Antarctic. The fifth, Florometra, of which there are two species in the Antarctic, 

 has ten other species ranging northwards from Cape Horn along the west coasts of 

 South and North America to the Behring Sea, westwards along the Aleutian Islands, 

 and southwards to the Pacific coast of Japan. 



It appears from these facts that the littoral crinoid fauna of the Antarctic is related 

 to that of the south of South America. Workers on the other four classes of echinoderms 

 have arrived at the same conclusion for those classes. Mortensen (1910, p. 100) wrote 

 of echinoids: "The South American (Patagonian-Chilean) littoral region must be re- 

 garded as the centre of the whole Antarctic — sub-Antarctic region ; a very great propor- 

 tion of the echinoids occurring in the Patagonian region are known from this region 

 alone, while others are also known from the Antarctic region." Koehler (191 2, p. 242), 

 after comparing the littoral asteroid, ophiuroid and echinoid faunas of the Antarctic, the 

 Magellan region of South America, the Kerguelen district, New Zealand and the Cape 

 concludes: "II ressort clairement de cette discussion que la faune antarctique des 

 Asteries, Ophiuries et Echinides, — du moins en ce qui concerne les especes littorales, — 

 a son point de depart dans la faune subantarctique des cotes de la pointe de I'Amerique 

 du Sud. Les comparaisons que nous avons faites, la composition et les rapports des 

 faunes etablissent ce fait d'une maniere indiscutable." Ekman (1925, p. 187) writing of 

 holothurians concludes: "Hier mochte ich nur die Meinung aussprechen, dass die von 

 anderen Forschern hervorgehobene, verhiiltnismassig nahe Verwandtschaft der ant- 

 arktischen Litoralfauna mit derjenigen des Magellangebietes auch betreffs der Holo- 

 thurien Giiltigkeit hat, und dass allem Anschein nach beide aus einem gemeinsamen 

 Entwicklungszentrum herstammen." 



There is only one other species of Eiimorphometra than those listed above; it is 

 E. hirsuta (Carpenter) from Marion Island. Marion Island belongs to the Kerguelen 

 group of islands comprising Kerguelen itself. Heard Island, the Crozets and Marion 

 Island. It possesses in more groups of animals than one a characteristic littoral fauna, 

 partly related to, or having species in common with, those of two other areas, the 



