AUSTRALIAN CAINOZOIC (tERIIAET) DEPOSITS. 55 



anterior and in the antero-lateral interambulacra there are large 

 primary and secondary tubercles irregularly arranged and sparsely 

 distributed, but occupying the whole of the spaces. The primaries 

 have a perforated mamelon, crenulated boss, and a flat scrobicule. 

 The edge of the ambitus is rather sharply rounded. The actinal sur- 

 face slopes upwards in front anterior to the mouth, and is more or 

 less convex posteriorly, on account of the sharp keel of the posterior 

 extremity of the interambulacral actinal plastron. The mouth is 

 slightly sunken anteriorly ; and the posterior lip is rounded and 

 projects downwards slightly, being, unlike the rest of the circum- 

 ference of the opening, very tuberculate (PI. III. fig. 16). The 

 actinal anterior and lateral ambulacra form short and almost smooth 

 avenues ; and the posterior ambulacra form wide, almost smooth 

 bands extending from the subanal fasciole on either side of the keel 

 to the sides of the mouth and behind the posterior lip. The anal 

 system is large, and almost circular in outline, and is situated in the 

 obliquely truncated posterior extremity, of which it occupies nearly 

 one half (PL III. fig. 17). The subanal fasciole is closed, heart- 

 shaped, and reaches to the point of the keel of the plastron. The 

 poriferous areas of the anterior odd and paired ambulacra on the 

 actinal surface show a few slit-like pores surrounded by a scrobicule- 

 like rim, which occupy the position of large tubercles. There are 

 also corresponding pores in the posterior ambulacral zones close to 

 the mouth. The tuberculation of the anterior interambulacra on 

 the actinal surface is larger near the mouth, and so is that of the 

 lateral interambulacra ; but the tubercles diminish in size and in- 

 crease in number towards certain points on the ambitus; within 

 the posterior actinal interambulacral space the tubercles radiate 

 from the point of the keel, and the largest are the remotest from it. 

 The mouth is large, broader than long, curved in front, and en- 

 croached upon behind by the projecting posterior lip. 



Length 2 T 8 ,j- inches, breadth 2 T 7 ^, height of vertex l T 5 ,j inch. 



Locality. — Tertiaries of the Murray river. 



Eupatagus Laubei, sp. nov. Plate III. fig. 18. 



The test is thin, depressed, elliptical in outline, but narrow and 

 somewhat pointed posteriorly. There is slight truncation of the 

 posterior interambulacrum. The antero-lateral and posterior 

 petals are nearly equal in length and breadth, and are lanceolate, 

 the anterior pair diverging more than the others. The poriferous 

 zones of both ambulacra are equal in breadth, are slightly sunken ; 

 and the anterior poriferous zone of the antero-lateral petals is the 

 smallest. The pores are conjugate, those of the antero-lateral zones 

 being the largest ; and in both ambulacra those of the inner row are 

 rounder and smaller than those of the outer, there being 13 or 14 

 rows in each petal. The interporiferous zone is slightly convex, 

 and has miliaries and third-sized tubercles ; and miliaries crowd the 

 elevations between the successive pairs of pores. The anterior odd 

 ambulacrum is nearly flush, bounded by tubercles larger than those 

 within its area, and contains a few pores. The apical system ia 



