CALCAREOUS SPOXGES. 781 



Although the genus Eilhardla was abandoned by Dendy 

 [1892 B], we now consider that it is fully entitled to i^ecog- 

 nition. 



The only known species is : — 



1. E. SCHULZEI PoUjaeff. 



Eilhardla sclmdzei PolejaefF [1883]. 



Family 9. AMPHORISOID^ Dendy [1892 BJ (emend.). 



Diagnosis. Flagellate chambers ranging from elongated and 

 radially arranged to small, spherical a.nd irregularly scattered. 

 With a distinct dermal cortex supported by a skeleton of 

 tangentially placed radiates to which oxea may be added. 

 Some or all of the dermal radiates with large apical I'ays, 

 which project inwards through the chamber layer to a greater 

 or less extent, and form the principal part of its skeleton. 

 No articulate tubar skeleton, but sometimes, in the leuconoid 

 forms, a confused skeleton of quadriradiates in the chamber 

 layer. Nuclei of collared cells probably always apical. 



The most conspicuous feature of this family lies in the large 

 dermal or subdermal quadriradiates with centripetally directed 

 ajDical rays. >Such spicules may indeed be present in certain 

 species of Leucandra, but in such cases they are always associated 

 with a confused chamber-layer skeleton of scattered triradiates, 

 which is never the case in the Amphoriscidse. If there be a 

 confused chamber-layer skeleton in this family it is found to be 

 composed of quadriradiates, which presumably have been derived 

 from the subdermal and subgastral quadriradiates themselves by 

 immigration. 



The evidence seems to indicate that Leucandra and Leucilla, 

 though difficult to separate in practice, owe their resemblance 

 largely to convei^gence, and that each has been independently 

 evolved from some sy conoid ancestor, in the one case directly from 

 some such form as Grantia, in the other through some such form 

 as Amjyhoriscus . 



In some Amphoriscidse large subgastral quadriradiates are 

 present, and in others, or even in the same, subgastral sagittal 

 triradiates (or quadriradiates) resembling the sagittal radiates 

 of the first joint of an articulate tubar skeleton. Whether the 

 centrifugally directed ray of the large subgastral quadriradiates 

 is homologous with the basal ray of the subgastral sagittal tri- 

 radiates, or whether it is an apical ray added to a tangential 

 triradiate of the gastral cortex, is a question which we cannot 

 decide without further evidence. 



