188 



Dimensions. — Length, 7*0; greatest width, 4*0; height of 

 aperture, 3*0. 



Locality. — Eocene ; glauconitic clayey sands, Adelaide-bore 

 -(6 exs.). 



3. Trichotropis subquadrata, -^pec. nov. 



Shell small, thin, fusiform, subumbilicated ; whorls five ; spire 

 conical, ratlier high, scalar, ending in a blunt apex of two Urate 

 whorls, the first one of which is relatively small. 



Spire-whorls two, with a sloping shoulder and angled post- 

 medially, anterior to which they are slightly convex. The spiral 

 ornamentation consists of four slender subacute threads on the 

 posterior area, of four stouter equidistant threads on the anterior 

 area, sometimes with a supplemental one in front of the posterior 

 thread, which is at the peripheral angulation. The transverse 

 ornamentation consists of oblique thread-like costul^e, with two or 

 three liner threads in the interspaces ; the intersections of the 

 spiral and transverse threads produce a very conspicuous and 

 regular tessellated ornament. 



The body-whorl is broad and short, rather tumid, with an an- 

 terior and posterior angulation, between which it is slightly 

 convex ; the base is flatly convex, and contracts very rapidly. 

 The spiral ornament consists of four threads above, six stouter 

 ones in the median portion and three on the base ; the transverse 

 ornament consists of slender costulae, which are directed back- 

 wards on the posterior area, incurved on the median area and 

 ecurved on the base ; the lirse are slightly denticulated at their 

 intersection wdth the costulse ; the interspaces are traversed by 

 two coincident raised lines. 



The aperture is rhomboid-rotund, inconspicuously channelled 

 at the front ; the outer lip is thin on the edge and smooth within ; 

 the inner lip is medially incurved, slightly reflected, but not con- 

 cealing the long narrow umbilical chink. 



Dimensions. — Length, 3'5 ; greatest width, 2*8 ; height of 

 aperture, 1'5. 



Locality. — ^Lower beds (Eocene) at Muddy Creek (4 exs.). 



This species, which is founded on what are probably immature 

 specimens, has a general resemblance to T. tahulata, from which 

 it difiers conspicuously in its neat tessellated ornament. 



4. Trichotropis triplieata, -w^c. nov. 



Shell small, thin, imperforate ; whorls four and a-half, convex ; 

 spire short, conical, ending in a blunt apex of two lirate whorls. 



Spire-whorls convex with three strong, equal, equi-distant, 

 -truncated lirae, with a fourth partially concealed at the anterior 

 ;suture, crossed by arched costulae which produce slight nodula- 

 tions on the lirae, and by lamellae of grow^th two or three in each 



