operation they are so liable to injury that, if packed in bulk and transported to long distances, a large 

 percentage would die and engender a rapid mortality among the survivors. The species is nevertheless 

 brought into some of the coast towns, such as Eockhampton and Gladstone, and there realises a price 

 corresponding with that of the ordinary commercial form. It is a question whether this oyster, Ostrea 

 mordax, might not be turned to more profitable account, by tinning or otherwise, by its collection and 

 conservation at temporarily-established stations in the immediate vicinity of it s most abundant development. 

 In dimensions the Coral Eock oyster rarely exceeds a length of 3 inches, and the lower or 

 concave shells in the finest esam])les examined were foHud to possess a holding capacity of one and a-half 

 fluid ounces. The reproductive phenomena of the species have been found by me to be essentially identical 

 with those hereafter described of the ordinary commercial species, Ostrea glomerafa, there being no 

 incubation of the brood within the mantle cavity as obtains in the more southern mud oyster, Ostrea edulis. 

 A small species of oyster which is tolerably abundant in various parts of Moreton Bay, and which 

 has in some instances encroached upon and taken possession of banks formerly occupied by the ordinary 

 commercial species, is the Ostrea crenulifera, of iSowerby. Tins species is usually less than one-half of the 

 size of the commercial oyster, and, while somewhat resembling it in general shape, may be distinguished 

 from that form by the more numerous, acuminately pointed denticulations of the peripheral border, which 

 are continuous, as in O. cristi-qaUi, with raised ridges of the external surface of the shell, and radiate 

 from the hinge or umbone to the periphery. Like Ostrea mordax last described, it is usually attached by 

 the left valve. The colour of the shells of this species are also very distinct, being of a uniform grayish- 

 white externally, and greenish within, the characteristic purple tints of O. glomeraia being altogether 

 wanting. Being too small for commercial purposes, the increase of Ostrea crenulifera on the banks 

 should, as far as practicable, be kept down, as, if left undisturbed, it will spread over the most favourable 

 breeding and spatting grounds, in addition to appropriating food material that would otherwise contribute 

 to the nourishment of the more valuable species. Illustrations of this diminutive oyster are given at Plate 

 II., Figs. 5 to 7. 



My attention has recently been directed by Captain Sykes, the Harbour Master of Rocthampton, 

 to an exceedingly remarkable variety of oyster, in some respects resembling Ostrea mordax, that occurs on 

 Eocky Island, off Keppel Bay, and which is illustrated by Figs. 2 to 4 of Plate IV. In this instance the 

 hollow beak-like prolongation or umbone of the attached shell, alluded to in connection with the variety 

 cucullata figured at Plate II., Fig. 2, is so abnormally developed that the movable or opercular valve 

 presents the aspect of a small hinged lid set upon the summit of an elongate corrugated tube. In the 

 upper of the two examples figured the relative dimensions of the two shells are so disproportionate that 

 ■while the right or opercular one measures just over an inch in its longest diameter, the left or attached shell 

 measures from its free edge to its base no less than six inches. This extraordinary modification is 

 apparently brought about through the oysters being crowded close together with no room for lateral 

 expansion, all growth being in consequence associated with the vertical elongation of the attached valve. 

 As shown in the diagrammatic sectional view of such an oyster given at Fig. y of the same Plate, the 

 cavity occupied by the living oyster extends through the anterior third only of the entire shell, the 

 remaining or basal two-thirds consisting of concentric cellular lamince that represent its successive 

 growth-lines. 



With respect to the shape and proportions of its component shells, this tubular oyster bears 

 a remarkable resemblance to a fossil group of bivalve mollusca known as the Hippuritidte, and which are 

 peculiarly characteristic of the cretaceous epoch. In the account of that family contained in Woodward's 

 " Manual of the Mollusca," the portion of a closely analogous oyster is figured under the title of Ostrea 

 cornucopice, a species originally established by Lamarck.' The original figures of Lamarck's type, 

 however, given at Plate 181, Figs, -l and 5, of the " Encyclopedia Methodique," published in the year 1827, 

 represent a rostrate oyster more nearly resembling the form of 0. mordax, illustrated at Plate II., Figs. 2 

 and 3 of this report, and which I identify with the Ostrea cucullata, of Born. In a foot-note to the latest 

 edition of Lamarck's " Animaux Sans Vertcbres," Vol. VII, p. 230, 1S36, the editors maintain, moreover, 

 that Ostrea cornucopite and 0. cucullata, as represented by tiie Paris Museum types, are varieties only of 

 one and the same species. In the same manner that the beaked cucullata has been shown to represent 

 a modification only of the ordinary Ostrea mordax, the very elongated tubular form here figured and 

 described may possibly represent an exaggerated growth of the variety cucullata. From an examination, 

 however, of a very considerable number of specimens of all ages, and in all of which the tubular develop- 

 ment of the attached shell is equally pronounced, I am inclined to regard it as a distinct species for 

 which the name of Ostrea cornucopicB — assuming it to be identical with Woodward's type of the same 

 name — may be most appropriately retained. Among other subsidiary characters, which may be cited a8 

 indicative of the close relationship of this variety cornucopicB with the ordinary Ostrea mordax stock, is 

 that of the same peculiar opaque purplish-pink of the external surface of the shells, with which is combined 

 a corresponding striate sculpturing of microscopic fineness The scar-like marking forming the attach- 

 ment of the adductor muscle on the opercular valve is also invariably of a dense black hue. The associated 

 clusters of this remarkable oyster, when viewed superficially, with little besides the opercular shells 

 visible, can in no way. be distinguished from the ordinary growth of Ostrea mordax, and it is only on 

 breaking them asunder and exposing the abnormally elongated lower valves that their distinctness becomes 

 apparent. The aspect and flavour of the meat of this oyster also corresponds with that of the ordinary 

 mordax, and of which from within the deeply excavated lower valve a much larger morsel is to be extracted, 

 than outward appearances at first sight promise. 



An oyster apparentlj' agreeing in all essential respects with the Ostrea cornucopia, here figured 

 and described, has been reported to me by Captain Sykes as occurring on the Locust Eock, Sweer's 

 Island, in the Gulf of Carpentaria. Further investigation will not improbably lead to its discovery in 

 some abundance on the Queensland coast-line, and in which case it is qualified, from a utilitarian stand- 

 point, to occupy a position equal with that of its nearest allied congener, Ostrea mordax. 



Although an oyster identical with the so-called mud oyster, Ostrea edulis, of the more southern 

 colonies has not been obtained from Queensland waters, a species bearing some resemblance to it has 

 been sparingly procured by me with the aid of the dredge in Moreton Bay, and is not infrequently 

 washed up in a much eroded state on the outside beaches. A highly characteristic feature of this species 

 is the single large indentation of its free margin, and which gives to its otherwise sub-orbicular shells a 

 saddle-shaped contour. It has also a peculiarly thickened margin, the outer edge of which when fresh 

 from the sea is coloured a delicate rose pink. A figure of a single valve of this oyster, and also a profile 



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