Catalogue of Non-Calcareous Sponges. 251 



The genus is here employed in a somewhat more restricted 

 sense, however, than was intended by von Lendenfeld for 

 Sigmatella. That author's diagnoses* make no sharp distinction 

 between Marshall's Phoriospongia and his own Sigmatella. If, 

 however, we restrict Phoriospongia to species with monactinal 

 megascleres, as was done by Marshall, and reserve Chondropsis 

 for those with diactinal megascleres, we shall have a very natural 

 distinction. The occasional styli observed by von Lendenfeld in 

 species of his Sigmatella, and by Carter in Chondropsis., were 

 probably abnormal or accidental ; in all cases the diactinal 

 spicules predominate. 



Unfortunately, Carter's type species of Chondropsis (C. 

 arenifera) is not a good example of the genus, being devoid of the 

 characteristic sigmata. He givesf no diagnosis, however, and 

 terms his group "Chondropsina," which is co-extensive with his 

 one species, " provisional." The genus Chondropsis may, there- 

 fore, be really considered as a new one, now for the first time 

 defined. 



I have very good evidence of an Ectyonine origin for this 

 genus, but have not space to enter into the question here. 



Chondropsis kirkii, Carter, sp. 



Dysidea kirkii, Carter, A.M.N.H., March, 1885, p. 216. 



(?) Sigmatella australis, Lendenfeld, Monograph of Horny 

 Sponges, p. 611. 



Sigmatella corticata, Lendenfeld, Monograph of Horny Sponges, 

 p. 618. 



The sponge is massive, often compressed but thick, sometimes 

 digitate. The vents are usually large and conspicuous. The 

 surface is smooth or minutely conulose and usually finely reticu- 

 late. The texture is compressible, and the colour in spirit pale 

 grey. 



The main skeleton is a very beautiful, irregular, tracery-like 

 network of very fine-grained sand-fibre. There is a close-meshed 

 dermal network of similar sandy fibre. The spicular elements are 

 greatly reduced, though the megascleres may still be observed in 

 radiating: tufts towards the surface. 



* Monograph of Horuy Spouges, pp. 598, 611. 

 t A.M.N.H., February, 1886, p. 122. 



r2 



