BCHINODEBMATA.' ^ 177 



neoting or southern Australian currents, which form probably the 

 northern boundary of the Antarctic circle, and along the lines of 

 which some species are now satisfactorily known to be extensively 

 distributed*. This south-westerly current leaves on its east the 

 western shores of Australia, and it seemed to be interesting to make 

 a definite examination of this question : Have the species in extend- 

 ing westward along the northern shores of Australia, and thence 

 southward, become specially modified in their journey ? 



Interesting as such a discovery would have been, it must be said 

 that the view that there might be a fauna special and peculiar to the 

 western coast of Australia cannot be in any way sustained either by a 

 consideration of the Echinoidea of the present collection or by a 

 general review of the distribution of the Order. 



The voyage of the 'Gazelle' resulted in the discovery at Naturalist 

 Channel, or Mermaid Straits, of four of the species noted in our list 

 — Salmads sulcata, Echinometra lucunter, Lovenia elongata, and 

 Breynia australasice ; Sahnads alexandri {globator) is known from 

 the west coast ; and all the following species would appear to be 

 found on the westerly as well as the easterly coasts of the continent : 

 — Oonioddaris geranoides, O. tuharia, Centrostephamis rodgersi, 

 Amhlyjoneustes griseus, A. pallidus, Microcyphus zigzag, Sphcer- 

 echinus australasice, and Eehinocardiv/m australe ; or about 25 per 

 cent, of the Echinoidea found on other parts of the Australian coast 

 have already been foun^ on the western shores, and no species are 

 known to be peculiar to them-. 



It is, no doubt, reasonable to suppose that the species which are 

 widely distributed in the Indo-Paciflc wiU be found on the western 

 coast of Australia, and that the more southerly forms wiU be repre- 

 sented by the species oi'Amhlypneustes, Mierocyphus, or Solopneusies, 

 which we are in the habit of regarding as truly " Australian." 



A somewhat similar story is told by the Ophiuroids. 



Tin lately fourteen species of Asteroids were known only from 

 Western or South-western Australia ; but Mr. Woods reports Culdta 

 pentangularis from N.E. Australia, Pentagonaster duheni from S. 

 Australia, and Tosia australis from S. Australia and Tasmania; 

 while the present collection enlarges the range of Patiria erassa. 



Although there appeared at one time to be good reason for dis- 

 agreeing with Martint, the present amount and weight of evidence 

 in our hands goes to point to the existence of a tropical oceanic 

 fauna ; to-day, as in those Tertiary times when a wider sea separated 

 the Australian from the Asiatic continent, there are forms whose 

 breadth of range is coincident rather with isothermal lines than 

 topographical boundaries. 



For the elucidation of the details of this tropical fauna, we may 

 look with almost more than confidence to the information afibrded 

 by the species of Crinoids : here, however, the cabinet naturalist can 

 as yet oaly appeal to the collector. 



* Evidence as to this was given by the earlier collections of the ' Alert ' in 

 the Straits of Magellan (see P. Z. S. 1881, pp. 1-141). 



t Notes Leyd. Mub. ii. p. 73 et seq. 



N 



