211 
small conical cup. Eadial plates oblong, and apparently spreading ; bodies and limbs 
of nearly equal lenglh. Sinuses long, narrow, parallel-sided, and nearly equally 
excavated between the radial and deltoid plates in two planes, the proximal or longer 
sloping away to the summit, the lower or distal directed towards dhe base, and shortest 
of the two. Eadio-deltoid sutures strongly V-shaped. Tho deltoid plates are large, 
shai'ply lanceolate, and their surfaces probably a little concave. Ambulacra very long, 
narrow, parallel-sided ; lancet plates slightly exposed ; side plates small, at least forty 
on each side, ambnlacral grooves rather deep, and much crennlated. Spiracles, 
hydrospires, and mouth unknown. Sculpture of radial and deltoid plates parallel to 
their outlines ; that of the former consisting of ridges, S6|)arated by corresponding 
depressions ; but on the latter the V-shaped lines become sub-imbrieate. 
Obs. 1 am constrained to place this anomalous form provisionally in 
Mesohlasius, although sensible that this is far from being its correct resting place. 
The general outline, contracted summit, and covered lancet plates, separate it at once 
from Peniremites, as that genus is now understood. The same characters indicate 
as a near ally, but the large lanceolate deltoid plates quite forbid such 
a reference. The only other genus of the family Peutremitidfe, the family to which the 
Blastoid clearly belongs, is Mssoblastus, E. and C. The resemblance between this genus 
and our species is so far identical that, in both, the deltoids are visible in a side view 
and conspicuous, the ambulacra narrow, without being linear in the sense as in the genus 
^fetablastus, and there is to some slight extent a resemblance in form. In other 
features, on the other hand, AT. ? australis does not conform to tho structure, of 
dfesoWas/MSj and it is possible that a new gonus will be required for its reception. I 
am, however, not prepared to deny that it may not be an abnormal Mesoblasius, with 
both deltoids and base rather larger than usual in species of the latter. 
A very peculiar feature is exhibited by this specimen, which, if real, and not 
superinduced by distortion or crushing, will separate it from all known Blastoids. At 
the radio-deltoid sutures the two outside ambulacra are bent down at a sharp angle, 
ollowing the bi-pyramidal outline of the calyx. From tho appearance of certain 
uiurkings I was led at first to regard this as the result of fracture, but the bilateral 
symmetry, and undistorted state of the calyx would appear to indicate otherwise. To 
restore these ambulacra to tho evenly convex outline found in Blastoids, in which the 
^'mbulacra extend beyond tho periphery, wmuld so disarrange the radial plates as to 
remove all semblance in tho specimen to a Blastoid at all. I am therefore constrained 
0 regard this angulation of the ambulacra as, to some extent, a feature of the species, 
is curvature is met with in several genera, Mesoblasius, SoJiizoblastus, and especially 
'‘'unaiocrinus, but not to such an extreme extent as in tho ])resent species. 
I shall look forward with interest to the acquisition of further specimens, with the 
riew of ascertaining how far tliis explanation of its structure holds good in M. ? australis, 
hoc. and Horizon. Eockhampton District * (O. W. Be Vis ) — Glympie Beds. 
Family— GEANATOBLASTIDAil.t 
Oe?ius—GBA]SrATOCRimiS, Troost, 1849. 
(Amer. Jour. Soi., viii., p. 420; Emend., Etheridge fil. and Carpenter, Catologne, loc. cit., p. 238.) 
Geah-atoceinus ? WAcnsMUTmi, sp. noo., PI. 7, fig. 10. 
El Under this' name is figured the first discovered remains of an Australian 
^^stoid, and it affords me great pleasure to associate it with the name of Mr. Chas. 
* See note, p. 199. 
t Etheridge fil. and Carpenter, Catalogue, loc. cit., ir. 237. 
