BV E. F. HALLMANN. 333 



Spicules. — (a) The oxea, which range in length, with incrensing 

 stoutness, from very rarely less than 220 to about 950 /x and 

 attain a maximum diameter of 31 /x, are very slightly curved, 

 fusiform spicules, tapering from the middle of their length 

 gradually to sharp points, and peculiar in the fact that their 

 outer or c<mvex side is curved somewhat angulately as compared 

 with their concave side. The last-mentioned feature is usually 

 best marked in the stoutest spicules As modifications of the 

 oxea, a few styli occur, which are evidently the result of a partial 

 atrophy as regards length, and the rounding off of the extremity, 

 of one actine. Further, a peculiar abnormality is occasionally 

 shown, perhaps too rare to be considered of phylogenetic signi- 

 ficance, in which the spicule is provided near one extremity with 

 one to several short accessory actines, so as to resemble a 

 Tetraxonid mesoclad. 



(6). The styli are straight or slightly curved, somewhat fusi- 

 form, and gradually sharp-pointed at the apex. They measure 

 from 160 to 250 /x in length, and are at most 9 /x in diameter. 



Loc. — Port Jackson. 



Remarks. — The species is, without doubt, of the same genus as 

 Uymeniacidon (?) foetida Uendy(ll), concerning whose correct 

 generic designation, however, there is considerable difi'erence of 

 opinion. It has been referred by Topsent(44) to the genus Amor- 

 phinopsis; by Dendy at a later date(15) to LeucophUtus; and by 

 Lindgren(30), Thiele(42), and again quite recently by Hentschel(21), 

 to Ciocalyptii. I cannot agree that such species, possessing a 

 halichondroid main skeleton of oxeote spicules and a dermal 

 skeleton of erect styli, are correctly assignable to Ciocalypfa; 

 nor can I see any better reason why they should be referred to 

 Leiicophloeus, the type-species of which, L.massalis Carter (6), 

 besides lacking their characteristic dermal skeleton, has a 

 main skeleton composed of styli. On the other hand, in the 

 forms of their spicules, Hyineniacidon (?) fatida and llenUrd 

 nvcyarrhapJiea agree with Carter's Amorphinopsis excaiuuis 

 very closely ; though, unfortunately, we do not know whether 

 in this, the type species of Amorphinopsis, the stylote spicules 

 form a dermal skeleton. There is, however, a probability that 



