REPORT ON THE CALCAREA. 41 



(Haeckel), neither of the Challenger specimens exceeds 18 mm., including the collar 

 fringed by fine linear acerate spicules 4 mm. in length. 



Colour. — White and yellowish. 



Habitat. — Station 36, April 23, 1873; off Bermudas; depth, 32 fathoms; mud. 

 Station 209, January 22, 1875; lat. 10° 10' N., long. 123° 55' E. ; Philippine Islands; 

 depth, 95 to 100 fathoms ; mud. 



Sycon arboreum, Haackel, sp. (PI. I. fig. 4). 



Sycandra arborea, Haeckel, Kalkscliwamme, Bd. ii. p. 331. 



There are four specimens of this Sponge in the Challenger collection, each presenting 

 a colony of 9 to 13 individuals (PI. I. fig. 4). The measurements of the spicules agree 

 with those of Haeckel, the only .differences being the length of the apical ray of the 

 gastric cpiadriradiate spicules, which, usually exceeding the extreme length of 0'08 mm. 

 given by Haeckel, not seldom reaches 0"25 mm., and the length of the acerate spicules 

 of the collar, which are never longer than 1 mm., and often still shorter (0"5 to I mm.). 

 The specimens were not particularly well preserved, but nevertheless, strange to say, the 

 epithelium of the outer surface could be discerned more perfectly than I had ever seen 

 it before, even by the aid of the osmic acid and gold methods. Accordingly, the course 

 of the intercanals could be studied very easily, and I must state that the intercanals and 

 the radial tubes of Sycon arboreum, as well as those of Sycon elegans, Sycon raphanus, 

 Sycon quadrangulatum, &c, are by no means regular enough to admit of their geometric 

 outlines being utilised for systematic purposes (Haeckel '), much less for the subdivision 

 of the genus into sub-genera. Moreover, such a subdivision is unnecessary, for all the 

 species of Sycon hitherto described can be very easily distinguished one from another 

 by means of other characters. 



The Challenger specimens of Sycon arboreum, like those examined by Hasckel, are 

 all from the southern or eastern coast of Australia. 



Colour. — Dirty yellowish. 



Habitat. — Station 162, April 2, 1874; off East Moncceur Island, Bass Strait, Australia; 

 depth, 38 to 40 fathoms ; sand. 



Grantia, Fleming. 



Syconidae with articulated tubar skeleton, with radial tubes which have lost every 

 trace of individuality, owing to the existence of a thin, yet quite independent, cortex, 

 its skeleton consisting principally of triradiate spicules. 



1 Kalkschwamme, Bd. ii. p. 290. 

 (zool. CHALL. EXP. — pakt xxiv. — 1883.) Aa 6 



