III.-DESCRIPTION OF THE SPECIES. 



Group KER ATOSA, Grant, 1861. 



Ceraospongice, 0. Schmidt, 1862. 



EuspongicB, Duchassaing de Fonbressin and Michelotti, 1864. 



Ceratina and Psammonemata (e. p.), Carter, 1875. 



Porifera with horny skeleton devoid of proper spicules. 



Family Darwinellid^, Merejkowsky, 1878. 



AplysinidcB {e. p.), F. E. Schulze, 1878. 

 Aphjsillince, v. Lendenfeld, 1883. 

 Aplysillidce, Vosmaer, 1884. 



Keratosa with large pouch-shaped flagellated chambers communicating by means of 

 numerous pores on their walls with inhalent cavities, by means of one wide mouth with 

 exhalent cavities ; ground-mass without granules, transparent ; axis of fibres thick. 



lanthella, Gray. 



Veroiigia (e. p.), Ehlers. 



Darwinellidoe, the fibres of whose skeleton contain true cells. 

 lanthella flciheU if or mis, Pallas, sp. (PI. I.; PI. II. figs. 1-7). 



Spongia jiahelliformis, Pallas, Elenchus Zoophytorum, p. 380. 

 lanthella flalelliformis, Gray, Proo. Zool. Soc. Lond., p. 49, 1869. 

 Verongia flalelliformis, Eblers, Die Esper'schen Spongien, p. 11. 



This species is represented in the Challenger Collection by two specimens both from 

 the Eastern Coast of Australia ; one of them may be seen drawn of natural size on PL I. 

 Their shape, in accordance with the specific name of the animal, is that of a thin leaf 

 terminating in a short stem ; which latter in both cases is of irregularly cylindrical outhne 

 and about 25 mm. long by 12 mm. broad. 



The Skeleton. — The constituent elements of the leaf-like part of the skeleton admit 



