136 



THE VOYAGE OF H.M.S. CHALLENGER. 



Till. —THE GEOGRAPHICAL AND BATHYMETRICAL DISTRI- 

 BUTION OF THE CPJNOIDS. 



A. Geographical Eange. 



The geographical distribution of the Crinoids is fully as extensive as that of the other 

 Echinoderms. Comatulae range between the two parallels of 81° N. and 52° S., while 

 the corresponding limits for the stalked Crinoids are 68° N. and 46° S. Some genera, - 

 such as Actinometra and Pentacrinus, occur in shallow water everywhere, or almost 

 everywhere, within the tropics ; though Pentacrinus has not yet been obtained in the 

 Pacific east of long. 170° W., nor between the meridians of 5° W. and 120° E., its 

 nearest approach to the Indian Ocean being the Moluccas. Metacrinus, on the other 

 hand, has been found in the neighbourhood of Singaj)ore ; but is otherwise almost 

 entirely limited to the tropical regions of the West Pacific, ranging, however, as far 

 north as Japan ; while Pentacrinus ivyville-thomsoni occurs in the Atlantic as far north 

 as lat. 45°. HoJopus, however, bas never been obtained out of the Caribbean Sea. 



Of the stalked Crinoids Rhizocrhms has the farthest northern range (68° N.), but it 

 has not been met with more than once (Station 122), or possibly twice (Station 323), 

 south of the equator, and is limited to the Atlantic and the Caribbean Ocean. Bathycrinus, 

 while rangino- throuoh 1 10° of latitude in the Atlantic and Southern Oceans, does not occur 

 in the Pacific at all. Antedon, on the other hand, is cosmopolitan, five species inhabiting 

 the Arctic Ocean, while the genus is also well represented in the Southern Ocean. It is 

 curious, however, that so far as I am aware, there are no museum specimens, nor any 

 records of Comatulae from New Zealand. 



As a general rule, the individual species of Crinoids are much limited in their range, 

 though there are a few well marked exceptional cases. Both species of Ehizocrinus occur 

 in the east as well as in the west Atlantic, Ehizocrinus lofotensis ranging 'from the 

 Lofoten Islands to 9° S. or perhaps to 35° S.; while three species of Pentacrinidaj occur 

 in the South Pacific near the Kermadecs, and also among the Philippines, as the following 

 list shows : — 



