BY E. P. KALLMANN. - 507 



in A. victoriana) to vertical planes; in some parts, however, — 

 more especially in the processes— a slight tendency towards such 

 an arrangement is occasionally exhibited. A further notable 

 point of difference is the frequency of occurrence, in the present 

 species, of megascleres disposed more or less perpendicularly to 

 the tibres, — with their bases implanted therein, — in the manner 

 of echinating spicules. The main fibres are composed chiefly or 

 (not seldom) almost entirely of spicules, an-anged usually in a 

 loose, often in a more or less dishevelled or somewhat plumose 

 fashion, and are usually between 100 and 200/x in stoutness: in 

 the oldest portions of the sponge, however, they occasionally 

 attain a diameter of from 300 to 400/^.. The amount of spongin 

 cementing their spicules is rather variable, but is seldom suffi- 

 cient to form a well-defined sheath; as seen in cross-section, the 

 outline of the fibres is very irregular. The connecting fibres are 

 uniserial to multiserial in spiculation, and are relatively more 

 sponginous than the main fibres. But very few megascleres are 

 scattered between the fibres. Sigmata (of two sizes) and micro- 

 strongyla occur in great abundance throughout all parts of the 

 interior, together with moderately numerous trichodragmata and 

 singly scattered trichites; the last-mentioned, howe\er, are not 

 very evident owing to their extreme tenuity. In the dermal 

 membrane, sigmata are again very abundant, and single trichites 

 almost equally so, but trichodragmata and microstrongyla are 

 extremely rare, and megascleres are altogether absent. 



Spicules. — {{.) The megascleres are styli and relatively few 

 oxea — the proportionate number of the latter variable, ranging 

 from less than 1 in 100 (in the type-specimen), occasionally to 

 as many as 1 in 10. Though somewhat scarce as echinating 

 spicules, the oxea occur in all the same situations in the skeleton 

 as the styli, and are undoubtedly only variants of them; never- 

 theless, transitional forms between the two are extremely rare. 

 The styli are slightly curved, with the curvatui-e most pronounced 

 in, and usually confined to their basal moiety; are evenly 

 rounded at the base, and of uniform or nearly uniform diameter 

 thence to beyond the middle of their length; and taper gradually 

 to a sharp point. The oxea — apart from their being diactinal — 



