New Echinoids from Australian Tertiary. 51 



Locality. — Cliffs at mouth of Sherljrooke River (type), and at 

 various localities along the coast in the neighbourhood. Also a 

 cast from the clays of Grice's Creek. Barwonian (? Eocene). 



Schizaster sphenoides, n. sp. 



Broadly ovate, depressed, somewhat pointed posteriorly. An- 

 terior groove indenting the ambitus to a depth of about 8 mm. 

 in specimens the size of the type. Dorsal surface rising steadily 

 to the vertex which is on a rather sharp median keel, and about 

 one-third of the total length from the posterior end. 



Lateral petals in rather deep grooves; the anterior laterals at 

 first curved and then straight. The posterior straight, lanceolate, 

 and very short. Odd ambulacrum in a deep groove, 6 or 7 mm. 

 deep in specimens the size of the type, with a flat floor and over- 

 hanging edge, so that the paired pores are not visible from above. 



Sternum flat, lanceolate, followed posteriorly by a pair of 

 tumidities, between which a shallow groove runs up to a subanal 

 concavity. Hind end truncate, overhanging above, the oval peri- 

 proct near the summit of the truncation. Peristome lunate, 

 visible from the front, with a well-developed labrum. Actinally 

 the posterior lateral ambulacra aie on broad areas that slope 

 strongly up to the ambitus medially and posteriorly. 



Thei'e are four pei'fotate basals. Tubercles larger on the 

 sternum, and crowded ; not so crowded, but as large on the other 

 interambulacra actinally. Small on the dorsal surface. 



Peripetalous fasciole crossing the antei'ior sulcus, in specimens 

 the size of the type, at about 5 mm. from the ambitus ; thence 

 straight to outer end of anterior lateral petal. A deep re-enter- 

 ing angle between the antero- and postero-lateral petals, and 

 straight between the posterior petals. Lateral fasciole given off 

 from the peripetalous at about a quarter of the length of the 

 anterior lateral petal from its outer end, crossing the ambitus at 

 about 10 mm. from the periproct, and passing below it at about 

 the same distance. 



Measuuemknts. 



Breadth. Height. A nte^o^Lateral Poste^o -^Lateral 



60 - - 38 

 60? (damaged) 35 

 47 - - 23 



(No. 1 is the figured specimen.) 



