74 



CONCERNING EDENTTELLINA. 

 By Charles Hedley, F.L.S. 

 Read 9th April, 1920. 

 The Australian fauna is remarkable for its wealth of oddities, 

 and in the Pelecypoda this quality is expressed by several excentric 

 forms such as CleidothcBrus, Dimya, Ephippodonta, Foramelina, 

 Myochama, Pseudochama, and Neotrigonia. To this assemblage is 

 now added Edenttellina. 



A small strange bivalve was once found by Deshayes among the 

 Eocene fossils of the Paris Basin. It took the form of a thin and 

 depressed scale ; on the umbo of the left valve was planted a spiral 

 nucleus like the tip of the gasteropod Strebloceras, the hinge of the 

 right valve carried a small cardinal tooth, and no muscular 

 impressions were perceptible. He had intended to present it as 

 a new genus, Ludovicia, and to place it next to Pandora. 



Deshayes, however, never finished his work and the little shell 

 lay unpublished for a generation, until Maurice Cossmann in 1888 

 described and figured it as Ludovicia squamula} He differed from 

 Deshayes in his estimate of its relationship and proposed to bestow 

 the genus in the family Galeommidse. Mr. W. J. Wintle kindly 

 points oat to rfl.e that Ludovicia is preoccupied by Ludovicius, 

 proposed by C. Rondani (Nuov. Ann. Sci. Nat., Bologna, vol. x, 

 1843, p. 43). According to Marschall the same name was after- 

 wards (Isis, 1845, p. 719) rendered as Ludovicia. 



Dredging within the Great Barrier Reef in August, 1906, 1 obtained 

 numerous specimens as disassociated valves of a small shell which 

 was provisionally labelled as Ludovicia, sp., and laid aside for 

 further consideration. Meanwhile, a related form had been taken 

 more than a thousand miles away, near Melbourne, and by Messrs. 

 Gatliff and Gabriel was described and figured as Edenttellina typica. 

 Sir Joseph Verco, who had previously made the acquaintance of the 

 species, then announced that it also occurred in South Australia. 



The present writer commented on the absence from Edenttellina 

 of characteristic pelecypod features and suggested that possibly 

 it might be the internal shell of a tectibranch ; the likeness between 

 the Parisian fossil Ludovicia and the recent Australian shell was 

 also noticed. 



Recent discoveries by Sir Joseph Verco have solved the problem as 

 to which class the perplexing stranger belongs. At Guichen Bay, in 

 South Australia, he procured better material than had been studied 

 by the Melbourne naturalists. This showed the right and left 

 valves to be united by a ligament and thus satisfactorily established 



^ Cossmann, Mem. Soc. Roy. Malac. Belg., vol. xxii, 1887 (1888), p. *i5, 

 pi. ii, figs. 21.-22. 



