NO, 3 CASSIDULOID ECHINOIDS — KIER I5I 



Genus AUSTRALANTHUS Bittner 



Australanthus Bittner, 1892. Sitzungsb, Kais. Akad. Wiss., vol. loi, p. 350. 

 Type species by original designation, Cassiduhis longianus Gregory. 



Medium size, oval, moderately inflated ; apical system monobasal ; 

 petals short, broad, open, strongly conjugate, with equal poriferous 

 zones, ambulacral plates beyond petals single pored ; periproct supra- 

 marginal, longitudinal, narrow ; peristome pentagonal ; bourrelets very 

 prominent, sharply inflated; phyllodes single pored with few pores; 

 buccal pores present ; adorally tubercles much larger, except for wide 

 naked zone in interambulacrum 5. 



Comparison zvith other genera. — Australanthus is similar to Har- 

 douinia in having an inflated test, a supramarginal periproct, promi- 

 nent, pointed bourrelets, and phyllodes with few pores. It differs in 

 having a monobasal apical system. 



Mortcnscn (1948, p. 222) considered Australanthus congeneric 

 with Procassidiilus and maintained Procassidulus even though it is 

 junior. Mortensen was not aware that Rhynchopygiis lapiscancri, the 

 type species of Procassidulus has a tetrabasal apical system which 

 immediately distinguishes it from A. longianus. Furthermore, its 

 test is much smaller, and its petals and bourrelets much less 

 developed. 



Lambert and Thiery (1921, p. 363) refer four other species to 

 Australanthus, all from the Senonian. One of them, Gabb's Cassidu- 

 lus micrococcus, is a Hardouinia. I have not seen any specimens of 

 the other three species, but according to Stoliczka's (1873, pp. 31, 32) 

 descriptions of his Cassidulu^s crassus and C. emys their apical sys- 

 tems are tetrabasal, and therefore these two species should not be 

 referred to Australanthus. The fourth species, Cotteau's Cassidulus 

 municri, is supposed to be Senonian according to Lambert and Thiery, 

 although Cotteau (1887, p. 515) says it is from the Lower Eocene. 

 It resembles Australanthus, but without seeing specimens of it and 

 without knowing the structure of its phyllodes, I hesitate to refer it 

 to this genus. 



Range and distribution. — Upper Eocene of Australia. 



DESCRIPTION OF TYPE SPECIES 



AUSTRALANTHUS LONGIANUS (Gregory) 



Plate 27, figures 1-4 



Cassidulus longianus Gregory, 1800. Geol. Mag., n.s., dec. 3, vol. 7, No. 11, 

 p. 482, pi. 13, figs. 1-3. 



Material. — Four specimens studied in the British Museum (Natural 

 History), two in the Lambert Collection, Sorbonne, Paris, and eight 

 in the U. S. National Museum. 



