OTSTEK-CULTUKE IN AUSTKALASIA. 573 



less an authority than Professor Huxley upon this very subject. 

 His closing paragraph to a lecture delivered at the Eoyal Insti- 

 tution, London, on the 11th May, 1883, upon "Oysters and the 

 Oyster Question," reads thus: "I, for my part, believe that the 

 only hope for the oyster-consumer is, first, in oyster-culture, 

 and, secondly, in discovering a means of breeding oysters 

 under such conditions that the spat shall be safely deposited. 

 And I have no doubt that, when those who undertake the 

 business are provided with a proper knowledge of the condi- 

 tions under which they have to work, both these objects will 

 be attained." 



When present in London at the delivery of Professor Hux- 

 ley's lecture I scarcely' anticipated being called upon, a few 

 years later, to take up its refrain at the Antipodes ; and with 

 the foregoing quotation from my first and much-esteemed 

 teacher in biology I feel that I can scarcely bring this essay to 

 a more appropriate conclusion. 



OSTKEA OKDEXSIS, S.-Kcut. 



Shells very irregular in shape, the most typical examples 

 somewhat elongate, arcuato-triangular, from one and a half 

 times to twice as long as broad, the convex border represented 

 by the anterior and the concave one by the posterior edge ; the 

 umbones acuminate. Usually attached by the left valve, which 

 may be adherent entirely or in part only to the suj)porting 

 fulcrum ; from one to three or four raised keels frequently 

 originating at the umbone of the right or unattached valve, ex- 

 tending to the distal margin, and there produced in the form of 

 projecting crests or lappets ; a series of smaller crestlike pro- 

 jections, frequently developed from the antero-lateral edges of 

 the left valve, when completely adherent, contributing towards 

 its firm attachment. The largest shells not exceeding ^in. 

 in length, the average being about jV^- 



Habitat. — Brackish water, attached to the leaves, stems, and 

 respiratory shoots of the white mangrove {Avicennia officinalis). 

 Collected by the discoverer at Adolphus Island, 0"rd Eiver, 

 Cambridge Gulf, Northern Territory of Western Australia, in 

 association with the surveying cruise of H.M.S. "Myrmidon," 

 Captain the Hon. F. C. P. Vereker, October, 1888. All in- 

 dividuals examined found to contain an abundance of mature 

 ova and milt. 



