Older Tertiary of Victoria. 91 



and 19 by 19. Var. paucicostatus, antero-postei'ior diameter, 

 22 mm.; umbo-ventral diameter, 21 mm.; others range about 18 

 by 17, and 15 by 14-5. 



Localities. — Grange Burn, between Forsyth's and Henty's, from 

 the days and sandy beds of the upper series ; Muddy Creek, from 

 the upper beds below the State School ; sandy clays of Jimmy's 

 Point, Gippsland, variety paucicostata seems fairly common at 

 this locality. Kalimnan, — Miocene. 



Observations. — -This species has usually been confused with 

 Pectunculus cainozoicus, T. Woods, but Mr. T. S. Hall was the 

 first to draw my attention to the fact that it was distinct. The 

 type locality for P. cainozoicus is Table Cape, and compared with 

 specimens from that locality, our present forms are much thicker 

 and stronger, more convex, with coarser radial ribbing, but much 

 finer radial striations. Hei'e again, as regards the genus, it 

 appears we must lose another old friend in Pectunculus, for, 

 according to Professor Tate and others, Axinaea should replace 

 it, but, according to Dall, Glycimeris appears to have the best 

 claims. 



Trigonia semiundulata, Jenkins. (Plate XV., Figs. 3-7). 



This species is a well known and characteristic form, described 

 by McCoy as from Bird Rock BlufF, and the specimens described 

 and figured by Mr. Jenkins are indicated by McCoy as having 

 been forwarded by him to an exhibition in London, and therefore 

 presumably from the same locality. This Bird Rock Bluff or 

 Spring Creek form is very consistent in shape and in the closeness 

 of the undulating anterior ridges. McCoy describes the undulat- 

 ing ridges as being "crossed, except on the anterior portion, by 

 rather faint impressed sulci radiating from the beak to the 

 ventral margin, nearly the same distance apart as the ridges of 

 the posterior slope." This faint impression of the sulci is not a 

 constant feature ; in some few specimens it is so extremely faint 

 as to be scarcely visible for a greater distance than half the 

 umbo-ventral diameter of the shell, and then only close to the 

 posterior radiation, whilst in others the impression is so deep as 

 to break up the undulating ridges into triangular nodes for about 

 a third of the antero posterior diameter. From the latter form it 



