Echinoid Radioles, Anaulocidaris. 167 
(BM) In the British Museum. 
1) Greatestulensthyie—fis = 2 a fF i, 15°D 
ae ae iGreatestwidthy@—b; 2. . 4.) 2 8B 
Cah Thickness along line x—y. . . . . 14 
Br pie --/ Thickness across blade at level d . . 1°9 
- Thickness in median line, same level . 1°5 
ext-fig. 63. 
ANNULUSAeen eye Pewee Tyee TES? 
Registered E 9356. From St. Cassian, Kuipsrein Collection. 
k, 1, m Three small specimens more strictly paletiform than 7. Two of them 
are broken. Registered E 9857—9. From St. Cassian, Kuipstein Collection. 
Paletiform radioles of A. Auchi are rare. Only fifteen are known to me, and 
of these some scarcely differ from trulliform radioles. Most are six-sided, but the 
sides are more rounded and less clearly cut than in A. testudo; see, for example, 
MM, j, and RAW, e. Three or four specimens are five-sided, with rounded angles. 
The paletiform radioles of A. Buchi further differ from those of A. testudo in 
the greater thickness of the blade; in the greater prominence of the ridges running 
from the handle to the distal angles; and in the frequent concavity of the outer 
face. Specimen BM, m (registered E 9359) shows these points of difference in a high 
degree. Its blade is five-sided; but as viewed from the inner face (fig. 255), the SW. 
side is much longer than the SE. side, and meets it at a very obtuse angle, so 
that the blade appears almost four-sided. The N. side is deeply concave; the NE. 
and NW. sides wavy; the angles rounded. The ridges are particularly prominent, 
and, where they converge, the handle rises up suddenly as a tapering pillar to a 
height of 3°3 mm. exclusive of the actual base, which is not preserved (fig. 254). 
The handle is distant from the S. margin by more than one-third the length 
of the blade. The outer face is deeply excavate (fig. 253). 
In the absence of intermediate trulliform radioles, ZirreL might well mistake 
these curious bodies for interambulacral plates; but it seems a strange coincidence 
that he should have associated them with the remiform and spatuliform radioles 
of the species to which they actually belong. The subsequent discovery of trulliform 
radioles led both Zirtet and Benecke to the correct interpretation of the paletiformes 
as radioles. BrENEcKE, however, does not seem to have appreciated fully the difference 
between paletiformes and trulliformes, but regarded five-sided specimens of the 
former as merely broken specimens of the latter. He says: «der angeblichen Naht- 
flachen der Asseln... sind... Bruchflachen des spathigen Kalkes». This explan- 
ation cannot apply to material now available. : 
The trulliform and paletiform radioles bought by the British Museum in 1851 
from Kuipstein were labelled by him with a new specific name in MS. They have, 
none the less, always been placed by the officials of the museum with the radioles 
labelled Cidaris Buchi. 
It has now been demonstrated that there are two distinct species of Anaulo- 
cidaris: A. Buchi in the Tyrol, and A. testudo in Bakony. It has further been 
shown that A. testudo is more specialised than A. Buchi, and, since it is found at 
