II.— DESCRIPTION OF SPECIES. 



Class CALCAREA, Bowerbank. 

 Porifera whose skeleton is composed of calcareous spicules. 



Order HOMOCCELA, Polejaeff. 



Calcarea without separate flagellated chambers, the whole of whose inner surface is 

 covered with flagellated cells. 



Family Asconid^e (Ascones), Hseckel. 



Of the characters of the Order. 



» 



Leucosolenia, Bowerbank. 



Of the characters of the Family. 



Leucosolenia poterivm (?) Haeckel, sp. (PI. III. figs. 1, 2). 



Ascetta primordialis, var. poterium, Hseckel, Kalkschwamme, Bd. ii. p. 1G. 

 Clafhrina poterivm, Ridley, Proe. Zool. Soc. Lond., 1881, p. 133. 



One of the four varieties established by Prof. Haackel for his Ascetta primordialis, the 

 variety poterium has recently been elevated by Mr. Ridley to the rank of an independent 

 species. In this course Mr. Ridley was supported by the fact that the sponge, having 

 been previously found only in Australia, was also dredged in the year 1878 in Tom Bay, 

 south-west Chili, and proved, furthermore, to be constant in its main characters, notwith- 

 standing the distance between these two localities. As properties distinguishing the 



Note. — The technical terms : — gastric, subgnstric, tubar, subdermal, and dermal, are used here with the meanings 

 applied to them by Hseckel in his Kalkschwamme. All the measurements were made with instruments by R. Winkel, 

 of Gottingen. The specimens were examined by means of sections stained with picro-carmine and monnted in Canada 



balsam. The indication of the colour refers to the specimens preserved in spirit. 



