778 PROF. A. DENDY AND MR. R. AV. H. ROW ON 



Genus 40. Paraleucilla Dendy [1892 B]. 



Diagnosis. Canal system leuconoid. Skeleton of the chamber 

 layer composed of confused triradiates. Subdermal cavities 

 present, supported by an inner and an outer layer of quadri- 

 radiates, whose apical rays cross each other in opposite 

 directions. Dermal cortex with tangentially placed tri- 

 radiates, between wdn'ch lie large, longitudinally placed oxea. 



For illustrations of this genus see Haeckel [1872]. 



This genus was proposed by Dendy [1892 B] to receive Haeckel's 

 Lettcandra cuciimis, but abandoned by him in 1893 on the ground 

 that it was not sufficiently distinct from Leucilla. He also 

 pointed out that Polejaeff had previously proposed the name 

 Pericharax for the same sponge. Further consideration has, 

 however, convinced us that the dermal quadriradiates of 

 Leucandra cucumis are not really compai-able to the subdermal 

 quadriradiates oi Leucilla and other Amphoriscidse, being related 

 solely to the cortex and not to the chamber layer at all. We 

 therefore transfer the species to the family Grantiidfe, with which 

 it has much more in common than with any other family of 

 Oalcarea. We know nothing, however, of the position of the 

 nucleus of the collared cells. The first mentioned species of 

 Pericharax^ on the other hand, is P. carteri Polejaeft' [1883, p. 19] 

 which we have now shown to belong to the Leucascid-Leucaltid 

 line of descent. We cannot therefore associate Leucandra 

 cucumis with either Leucilla or Pericliarax^ and it therefore 

 appears to us that as it is clearly distinguished from other 

 Grantiidse by the presence of subdermal cavities with a special 

 skeleton, it is necessary to revive the genus Paraleucilla for its 

 reception. Haeckel, it is true, placed his Leucandra cucumiis in 

 the subgenus " Leucogypsa," but Bowerbank's name " Leuco- 

 gyjysia'^ if revived at all. which we think very undesirable, would 

 have to be reserved for Leucandra. 



The only known species is : — 



1. P. CUCUMIS Haeckel. 



Leucandra cticumis Haeckel [1872]. 

 Paraleucilla cucumis Dendy [1892 B]. 



Genus 41. Lamontia Kirk [1894]. 



Diagnosis. Sponge consisting of a single person Avith a specialised 

 pore-zone below the terminal osculum. Canal system 

 leuconoid. Skeleton of the chamber layer consisting of small 

 scattered oxea. Dermal cortex with triradiates in addition 

 to oxea. Gastral quadi'iradiates present. 



For illustrations of this genus see Kirk [1894]. 



