AUSTRALIAN (CAINOZOIC) TERTIARY DEPOSITS. 47 



by some authors Echinanihus testudinarius, and by others Clypeaster 

 testudinarius, that there can be no hesitation in identifying this fossil 

 with that species. Except in some slight points in which there is 

 great individual variation in the recent forms, the fossil agrees with 

 those which Gray called Echinanihus testudinarius and E. australice, 

 the latter of which has been absorbed by the former *. 



The species is interesting from its close resemblance to a Clypeaster ; 

 but it has no pores close to the sutures of the plates within the 

 ambulacra on the actinal surface. 



Locality. — Lindenow, Mitchell River, Eastern Victoria. 



Family SCUTELLID^E. 



Arachnoides Loveni, sp. nov. Plate III. figs. 6 & 7. 



The test is roundish, subpentagonal, flat, rising slightly towards 

 the apical disk, and slightly concave on the actinal surface. It has 

 the same longitudinal and transverse diameter. The apical disk is 

 slightly in front of the centre. 



The ambitus is sharp, and is incised at the end of each ambu- 

 lacral groove ; and there is a rounded excision at the periproct, which 

 is just under the margin. The ambulacra are grooved longitudinally, 

 and swell up on either side ; and they occupy about an equal space 

 with the interambulacra, where they are comparable. The poriferous 

 zones reach about halfway to the ambitus, and are broad and turn 

 in slightly. The ornamentation in the ambulacral spaces is oblique 

 and banded, but it is without any order on the interambulacra. 



On the actinal surface this oblique ornamentation is seen on 

 either side of the ambulacral groove ; and this groove enlarges near 

 the peristome, which is subcircular. Traces of sphasridia on one side 

 of the groove are observed. 



Length of large specimen 2 T 2 1J inch; breadth Scinch. 



Locality. — Mordialloc, Section 2. No. 1 and No. 3, and from soft 

 yellowish white limestone at the mouth of Curdies River, about 

 30 miles east of Warumbool, which is in the upper part of a series 

 underlain unconformably by Miocene calcareous clays. 



This species, eminently Arachnoidean, has, however, more de- 

 fined excisions on the ambulacra at the ambitus than either of the 

 living forms, A. placenta, Linn., and A. zelandice, Gray — the one from 

 the whole eastern coast of Australia, and the other from New 

 Zealand. The situation of the periproct is variable in the genus 

 Arachnoides, and is not invariably supramarginal. It may be marginal 

 and slightly sub- or inframarginal ; and this last appears to be 

 characteristic of the fossil forms. The resemblance between the 

 ornamentation, the sphaeridia, the actinal grooves, and the petals of 

 the ancient and modern forms is very remarkable. 



* Gray, Proc. Zool. Soc. Lond. 1851, p. 35; A. Agassiz, Rev. Echin. pt. iii. 

 p. 514. 



