270 



Transactions. — Zoohgy. 



distinction is untenable. Every gradation of keeling is observ- 

 able in the Australian Isidore (Rev. A. H. Cooke). 



Isidora tabulata, Gould (1848), sp. 

 Physa tabulata, Gould, Proc. Boston Soe. Nat. Hist,, vol. ii. 

 (1848), p. 214 ; U.S. Expl. Exp., vol. xii., p. 116, figs. 136 a, b. 

 Physa tabulata. v. Martens, Crit. List N.Z. Moll. (1873), p. 15. 

 Physa tabulata, Hutton, Man. N.Z. Moll. (1880), p. 30. 

 Aplexa tabulata, Hutton, P.L.S. N.S.W., vol. vii., p. 67. 

 Bali mis tabulatus, Hutton. Trans. N.Z. Inst., vol. xvii. (1885), 

 p. 57. Phjsa tabulata. A. H. Cooke, P.Z.S. (1889), pp. 139, 

 140, fig. 4 (radula). Bvlinus tabulatus. Hedlev and Suter, 

 P.L.S. N.S.W. (2), vol. vii. (1893), p. 627. Bullinus tabulatus, 

 Suter, Journ. de Conch., vol. xli. (1894), p. 233. 



The diagnosis is to be found in Hutton's Manual. 

 Fig. 1 represents the species after a copy from 

 Reeve (Conch. Icon., vol. xix., Physa, fig. 176), 

 kindly supplied with several others by Mr. Hedlev. 

 Taken from the figure the dimensions are — Shell : 

 length, 22 mm. ; breadth, 16 mm. Aperture : 

 length, 12 mm. ; breadth, 8 mm. I think it to 

 be a most useful thing to establish the following 

 rationis to help in separating the various forms : 

 i. Ratio between breadth and length of shell =1:1-4; ii. ratio 

 between breadth and length of aperture = 1 : 1*5 ; iii. ratio 

 between length of aperture and length of shell = 1:1-8. Here- 

 after I shall designate these rationis simply by i., ii., iii. 

 Hub. A mountain-stream, Bay of Islands (Drayton). 

 Type in the U.S. Nat, Museum, Washington. 

 I have not seen this species. 



Isidora tabulata, Gould, subsp. moesta, H. Adams (1861), subsp. 

 Physa moesta, PL Adams, P.Z.S. (1861), p. 144. Physa coro- 

 manddica, Dunker, Malac. Blatter (1862), p. 150. Physa 

 moesta, Hutton, Man. N.Z. Moll. (1880), p. 31. Aplexa moesta, 

 Hutton, P.L.S. N.S.W., vol. vii., p. 67. Bulinus moesta, 

 Hutton, Trans. N.Z. Inst., vol. xvii., p. 57, pi. xii.. fig. 12 

 (dentition). Bulinus moesta et coromanddica, Hedlev and 

 Suter, P.L.S. N.S.W. (2), vol. vii., pp. 627, 628. Bullinus moesta 

 et coromanddica, Suter, Journ. de Conch., vol. xli., p. 233. 

 The very short diagnosis is fortunately supple- 

 mented by a figure in Reeve's Conch. Icon., fig. 32, 

 the outlines of which I here reproduce (fig. 2). The 

 dimensions, taken from the figure, are — Shell: length, 

 17 iiiin. : breadth, 11mm. Aperture: length, 10 mm. : 

 breadth, 5 mm. The proportions are : i. •■= 1 : L5 ; 

 Fig. 2. ii. = 1 : 2 ; iii. = 1 : 1*7. 



