ONCHIDIID^ FROM AUSTRALIA AND THE SOLTH-WESTEKN 



PACIFIC ISLANDS 



i;v 

 Kkn. W. 1>i;f. I nam,, liivfrtt'ljiciti' Zoulof^ist, Aiibtniliaii Miiscuin. 



(Plate xxxviii.) 



I. — 1m i;(iiHMTi(»N. 



From (he t'ull()\Yiiig historical review ol' the family, it will be seen 

 that, since the discovery of Uiic/iidiinn tijiilui' hy Buchanan in ISOO, the 

 bi'ological affinities of the Oncliidiidaj have received the attention of many 

 of the eminent authorities of Mahicology. 



While much remains to be done to bring the knowledge of this group 

 into line with that we have of other groups, this paper may sei've as a 

 convenient summaiy for the use of Australian students, and since it has 

 had foi- its foundation tlie excellent wcu'ks of Semper, Plate, Joyeux-LafFuie 

 and many others, no apology need be oifered for the more or less extensive 

 quotations from these authors. 



The bulk of the material examined is preserved in alcohol in the 

 collections of the Australian Museum. The absence of marine aquaria 

 has made the much needed observations on the life and habits of even the 

 commonest forms almost impossible. 



Oiii-li'uUitni dilinelii is fairl}' common on the shoi-es of Port Jackson, 

 living either below watei% or under rocks between tide marks. O. ehaine- 

 leoii was not pleiitiful when search was made for it in its habitat on the 

 Lane Cove River in Mai'ch, June and October, 1918. Both these fonns 

 exhibited the chameleon-like property of changing their coloui"s, especially 

 when disturbed, or changed to a position of which the background was a 

 different colour to that fomnerly occupied. From this habit 0. chameleon 

 received its appropriate name from its author, but this property is not 

 remarked on by other authorities of the group. It may yet be shown that 

 the function of the dorsal eyes may be attributed to this property, i-ather 

 than their value to the animal in discerning attacks from such enemies as 

 PeridjiflKjIiiiiiti^ as was suggested by Semper. Tliis fish, it may be 

 mentioned, is not an habitant of Port Jackson. F'urthei-, my observations 

 have not sliowu that eithei' (). Jiinielli or 0. clndin-Jeon possess the lioming 

 habit that is attributed to Onr/iidiiin) by receiit authors^. The distribution 

 of the family is usually tropical and continental, but one form, OiichidelJa 

 liatelloides, Quoy and Gaimard, i-anges to the cold watei-s of South New 

 Zealand, and an un-named species has been mentioned by Woodward- 

 from the Ellice Islands in the Central Pacific. 



My thanks and appreciation in the prepai'ation of this paper are due 

 to Mr. C. Hedley, Assistant Curator of the Australian Museum, for his 

 ever ready and valued advice, and to Dr. C. Anderson of the same 

 institution for much assistance in the ti-anslation of foi^eign languages. 



1 Arey and Crozier — Proc. Nat. Acad. Sc-i. Wash., iv., 11, 1918, p. 319. 

 -■ Woodward— Proc. Malac. Sec, iv., 190U, p. 102. 



