214 
PACHYDOMUS, J. Morris. 
Pachydomus globosus, j. D. 8owerhy} 
PI. XVIII, Pig. 5. 
Meycidesmus glohosiis, J. D. Sowerby,18f38, in Mitchell’s Three Exped. Interior E. Australia, 
I, p. 15, pi. 1, fig. 1, 2. 
JPcichydoniUS, ,, J. Morris, in Strzelecki’s Phys. Descr. of N. S. Wales and V. D. 
Land, p. 272, pi. 10, fig. 2, 3. 
,, ,, P. McCoy, 1847, Ann. Mag. Nat. Hist., XX, p. 301. 
The shell is oval, ventricose, and a little longer than broad. Its valves 
are deep and regularly ventricose, and its beaks thick and recurving so as to 
touch each other. The external ligament is very strongly developed. The 
surface ornamentation consists of numerous concentric furrows of growth, 
irregular both in form and in distribution ; sometimes they are very deej) and 
broad, and sometimes narrow and superficial. The shell is so thick as to 
leave no trace of the external ornamentation on the internal cast of the shell. 
Dimensions. — This species can acquire very large dimensions. I have 
figured the only nearly perfect specimen sent me ; it is eight centimetres 
long, six and a half broad, and five and a half thick ; the test has an average 
thickness of two millimetres. 
Delations and Differences. — This species, in its general form, is 
very similar to E. nobilissima, which differs from it by the much less anterior 
position of its beaks, by a much greater regularity of the concentric folds of 
its surface, and above all by the thinness of its test, which is so thin as to 
allow the internal casts to reproduce and preserve the surface ornamentation. 
Eorizon and Localities. — This species was found at Wollongong 
(P. McCoy) and Illawarra, N. S. lYales ; at Spring Hill in Tasmania by J. 
Morris; and at Lochinvar (N.S.W.) by Mr. W. B. Clarke. 
Pachydomus ltevis, J. D. Soioerhy. 
PI. XX, Pig. I. 
Meyadesnins Icevis, J. D. Sowerby, 1838, in Mitcbell’s Three Exped. Interior E. Australia, 
I, p. 15, pi. 3, fig. 1. 
1 iVide R. Etheridge, Junr., Geol. and Pal. Q’land., 1892, p. 282; Stoliczka, Cret. Fauna S. India (Pal. 
Indica), 1871, pp. 83, 274.— W.S.D 
