732 REPORT— 1895. 



7. Criticisms on some points in the Summary of the Results of the 

 ' Challenger ' Expedition. By Dr. H. O. Forbes. 



8. Observations on the Marine Fauna of Hotitman's Ahrolhos Islands, 

 Western Australia. By W. Saville-Kent, F.L.S., F.Z.S. 



Mr. Saville-Kent's investigations of tlie marine fauna of Houtman's Abrolhos 

 Islands were associated with a visit he paid tbeiu in his capacity of Commissioner 

 of Fisheries to the Western Australian Government, and were conducted with the 

 particular object of advising that Government as to the conditions and prospects 

 the adjacent waters presented for the establishment therein of profitable oyster 

 or mother-of-pearl shell fisheries. 



Houtman's Rocks, or Houtman's Abrolhos, as they are variously charted, are 

 so named alter one of the early Dutch explorers in contradistinction to a coral 

 group, also known as the Abrolhos, lying off the coast of Brazil. The island 

 group discussed in this paper is a small archipelago, chiefly of coral origin, 

 situated between the latitudes of 29° and 30° S., about thirty miles west of Cham- 

 pion Bay and the important Western Australian port of Geraldton. 



As a result of his investigations Mr. Saville-Kent found that the ordinary 

 Australian rock oyster, OstrcBa glomerata, occurred there in tolerable abundance and 

 under conditions that would justify its being made the subject of systematic cultiva- 

 tion. The smaller West Australian variety mother-of-pearl shell allied to or identical 

 with Meleagrina ijnbricnta occurs very sparingly on the Abrolhos Reefs, but in the 

 Commissioner of Fisheries' opinion was not worthy of serious attention in face of 

 the unexpectedly favourable conditions he discovered to obtain there for the 

 introduction and acclimatisation of the larger and more valuable species, Meleagrina 

 margaritifera. This decision was arrived at as the outcome of an investigation of 

 the associated marine fauna, and which was found to present features of high 

 interest from both a utilitarian and a biological standpoint. 



The existing pearl and mother-of-pearl shell fisheries of Western Australia, as 

 associated with the larger species, have not hitherto extended further south than 

 Exmouth Gulf, in about lat. 22° S., and are consequently limited to the Tropics. 

 The fishery for the smaller species, Meleagrina hnbricatn, is confined chiefly to 

 Shark's Bay, three to four degrees south of Exmouth Gulf, and has in consequence 

 of the wasteful depletion of the banks in former years been reduced to a compara- 

 tively low state of productiveness. Among other operations initiated by Mr. 

 Saville-Kent, with the object of resuscitating the Shark's Bay fishery, has been the 

 experimental transportation to it and cultivation of the large tropical pearl shell 

 Meleagrina margaritifera. These acclimatisation experiments, althougli initiated 

 only on a small scale, have been attended with complete success. The large 

 mother-of-pearl shell has not only shown its capability of thriving in the colder 

 waters of Shark's Bay, but has within a year of its transportation to this exLra- 

 tropieal area commenced to freely propagate. 



The site selected for the foregoing experiments in Shark's Bay was the neigh- 

 bourhood of extensive banks of coral growths pertaining to the genus Turbinaria. 

 and from which reefs Mr. Saville-Kent obtained the remarkably large specimens of 

 this Madrepore that are now on view in the e.xhibition galleries of the Natural 

 History Museum, South Kensington. It has been determined by Mr. Saville-Kent 

 in the course of his Australian explorations that the genus Turbinaria represents 

 the group of Madrepores which in Australian waters enters most extensively into 

 the composition of coral reefs in the colder or extra-tropical limit of their distribu- 

 tion. This predominance of Turbinarians had been found by him to obtain at 

 Wide Bay, on the southern outskirts of the Great Barrier Reef in Queensland; in 

 the colder though more northern waters at the head of the Gulf of Carpentaria; 

 and, finally, in the Shark's Bay district of Western Australia. 



The conditions which permitted the successful acclimatisation of Meleagrina 

 margaritifera in Shark's Bay were found by Mr. Saville-Kent to be still more 

 favourably fulfilled around Houtman's Abrolhos. In and among this island group, 



