306 Cliapmaa and Gabriel : 



The recent examples of T. margaritacea, var. acuticostata from 

 Bass Strait determined by McCoy have all the requisite characters 

 of the fossil variety, and specimens in the Dennant collection from 

 Jemmy's Point exactly resemble them in the fewer number of ribs. 

 (See pi. xxvi. figs. 13«, h. 



T . Diargarifacea has been recorded from the Werrikooian (Pleis- 

 tocene) of Limestone Creek, Glenelg River, by Mr. J. Dennant.^ 

 On referring to the Dennant collection, however, we find the only 

 specimen of Trigonia from Limestone Creek there represented be- 

 longs to T . lainarcki. 



A variety of T. mar gar it acta, in which the scales of the ribs 

 are flattened out in an almost spatulate fashion, has lately been 

 described by Dr. J. C. Verco, from St. Vincent's Gulf, and else- 

 where along the South Australian shores, to which he gives the 

 varietal name, hednalli'} 



Distribution.— Bore 2, 198-200 feet. Bore 3, 226 feet. Bore 

 6, 154-158 feet; 158-161 feet. Bore 9, 315-326 feet. Bore 10, 

 230-254 feet; 264-296 feet. 



Fam. PECTINIDAE. 

 Genus PECTEN, Miiller. 



Pecten murkayanus, Tate. 



Pecten. murrayauus. Tate, 1886, Trans. R. Soc. S. Aust., 

 vol. viii. p. 105, pi. vii. figs. 5a, h. 



This species affords an interesting illustration of the close re- 

 lationship between many of oar Tertiary species of moUusca and 

 those now living, generally in lower latitudes, around the Austra- 

 lian coast and in the adjacent seas. P. marrayanus is clearly a 

 progenitor of the group of pectens represented by P. leopardu& 

 Reeve-3 (W. and N. Australia and New Caledonia); P. Solaris, 

 Born sp.* (China Seas and Amboyna); and P. kuhnholtzi, Ber- 

 nardi-'' (New Caledonia). In all four species, the costation and con- 

 centric ornament are precisely identical, if a fairly extensive series- 

 is taken. A constant character in all is shown in the crowding of 

 the concentric lamellae near the umbonal region, their opening out 



\. Hec. Geol. Siirv. Vic-t., vol. i., pt. ii., 1903, p. 146. 



2. Trans. Koy. Soc. S. Austr., vol. xxxi., 1907, p. •lii. pi. \xviii., fijrs. 1 .'5. 



3. Icon. CoiK-h, 18.52, pi. xxxii., flj,'. 145. 



4. Index Mus. Cats. Vind., 1778, pt. i., Testacea, pi. \i , tin 4- •'^*?'' ''•'^o So\verl).v, Thes. Conch. 

 1842, pt. ii., p. ,55, pi. xii., fijfS. 7, 8, 22. 



,5. .Journ. dc Conch., 1863, vol. viii., p. .'CS, pi. xiii., fiu. 1. 



