208 



the surface of tlie sand with much expedition. Our two species 

 of Pholads {Barnea similis and B. ai(strakisice) and Vcmerupis 

 ohesa burrow in stiff clay at low- water mark. 



Molluscs living beyond low-tide. — Those living on rocky bot- 

 toms present no special feature from those living between tide- 

 marks, except that a greater number of species occur, increas- 

 ing somewhat with the depth. The greatest variety of life- 

 occurs undoubtedly on rocky bottoms extending to a few fathoms- 

 in depth. Here haunt a large species of Octopus — Cypvfea 

 thersites, the Volutes, Ostrea Angasi, Pec ten laticostatus. The 

 delicate parchment-like shell of Acicula pidchella anchors to the 

 stems of seaweeds, and the delicate limpet, Nacellaparvn, creeps 

 upon them ; Waldheimia ciustralis also in the same position, and 

 fixed to other submarine bodies. Gastroclicena Tasmanica lives 

 in crypts which it excavates in limestone or in the thick test of 

 oysters. 



Molluscs living on soft bottom, beyond tidemarhs. — In shallow 

 water ranging to six fathoms life is very abundant, especially 

 among the submarine pastures of Cymodocea zosterifolia and 

 Posidonia australis, which afford secure protection against 

 ordinary wave currents, and are the favourite haunts of the 

 Sepias and Sepiolas among cuttlefish. Globose bivalves and 

 slender turrited shells here only are found. It is unnecessary 

 to enumerate the species inhabiting this region, but I may 

 indicate some of the novelties in respect to habit. Pinna Zea- 

 landica lives in large colonies anchored vertically in the mud 

 by means of its sharp apex and long byssal threads ; parasitic 

 on it are Crepidida immersa, Amcdthea conica, Placunanomia 

 lone, Hipponyx. The delicate Anatinas form deep burrows ; 

 Vtdsella ovata, Modiolaria Cumingiana, Sdiquaria australis, 

 and *S'. Tahitievsis burrow in sponges ; whilst Pecten asperrimus^ 

 is conversely the host of a soft red sponge : a species of Eulima 

 lives on Cidaris and other echiuoderms. 



The waters of St. Vincent Gulf are for the most part very 

 shallow, and little or no exploration has been carried beyond 

 a few fathoms, except in one instance only, to my knowledge, 

 in Backstairs Passage, whence was obtained a few mollusca, 

 from 32 fathoms, which have not been met with elsewhere in the- 

 Gulf, and some not at all. They are Erato lachryma ; Cardita 

 sp. ; Ga^trocliana lamellosa ; Limea, nsp.; Terebratidina can- 

 cel lata. 



In adding a few remarks on the subject of his paper, the 

 Professor pointed out that if the Port Creek and Largs Bay 

 were each to be fossilized, it would be found that the common 

 shells of the one were not the same as the common shells of 

 the other. He did not agree with the attempts that had been 

 made to place the various fossil localities in the Older Tertiaries 



