242 
Horizon and Localities. — Mr. Clarke found a single specimen of this 
speeies in a greyish sandstone near Maitland. Mr. Morris found it at Spring 
Hill, Tasmania. 
Ptekinea lata, F. McCoy. 
PI. XVI, Pig. 11. 
Fteronites latllS, P. McCoy, ISII, Syuop. Carb. Poss. Ireland, p. SI, pi. 13, fig. 7. 
jLvicilla lata, A. d’OrbIgny, 1850, Prod. Pal., I, p. 135. 
This is an elongated, depressed, suhtriangular shell of moderate size, 
and angular at the anterior extremity. The posterior margin is sinuous and 
joined by a regular curve to the ventral margin. The beak is small and 
placed at a short distance from the anterior extremity. The anterior ear is 
small and not distinct, the posterior is very large and ends in a sharp point. 
The hinge line is straight, slightly exceeds the anal margin, and so is a little 
longer than the shell proper. Two or three thin, long teeth, almost parallel 
with the hinge line, compose the hack part of the hinge. The external 
surface is nearly smooth, being crossed only by indistinct concentric lines of 
growth near the margins and towards the end of the posterior ear. 
Dimensions . — The length is three and a half centimetres, the breadth 
twenty-seven millimetres, and the thickness of the left valve two millimetres. 
Relations and Differences. — I agree with Woodward that there is no 
well-marked difference between Rterinea and Fteronites. The presence of 
the posterior teeth on the species I have just described leaves no doubt in this 
case. It differs from F. angustata, McCoy, by its much greater breadth, and 
by it sinuous anal margin. 
Horizon and Localities. — It is found in the Millicent limestone, 
Ireland, and in the limestone on the Upper 'Williams Hiver, Australia. 
Genus — AVICULA, Linneeus. 
Avicula sublunulata, L. G, de Koninch. 
PI. XVI, Pig. 4. 
This shell is of medium size, siihequivalved, elongated, and slightly 
oblique. Its hinge line is shorter than the antero-posterior diameter of the 
