LANUGONYCHIA FLABELLUM. Ill 



verse branches. Slender secondary end-rays 8-17 m long arise from the sides 

 and ends of the primary end-rays and their terminal branches. The basal parts 

 of these are directed obhquely backwards towards the centre of the spicule, but 

 they at once curve strongly outward, their distal and middle-parts being fairly 

 straight and directed obliquely outwards. Each of these secondary end-rays 

 bears a terminal verticil of relatively large, recurved spines, which appears as a 

 terminal disc with strongly serrated margin. These terminal spine-verticils, 

 which measure as much as 10 /x in transverse diameter, closely resemble the 

 terminal spine-verticils of the discohexasters above described. In examining 

 these remarkable spicules I gained the impression that their secondary end-rays, 

 the basal parts of which are in exactly the same position relative to the primary 

 end-rays as the spines, might be considered as hypertrophic spines. 



The amphiasters, which, as stated above, I beheve to be foreign, have 

 a shaft about 13 n long and 1.2 ^ thick, from each end of which arise three 

 branch-rays, sometimes 23 m long. These branch-rays bear secondary branches 

 at the end. 



The known species most closely allied to the sponge described above are 

 Mellomjmpha velata (Wyv. Thoms.), Lanuginella pupa O. Schm., and certain 

 rossellinas. It differs from all these by its spiculation to such an extent, how- 

 ever, that a new species must be established for it. About this there can be no 

 doul)t. It is more difficult to decide in which genus this species should be placed. 

 Is it to be assigned to one of the ah-eady established genera and if so to which 

 one, or is a new genus to be established for it? 



In regard to its internal microscleres and to its large pentactines Lanugony- 

 cliia flahellum resembles most closely Mdlonympha velata, the only species of 

 Mellonympha. Since, however, its body is lamellar and thin, since its dermal 

 spicules are reduced hexactines, mostly with only from one to four fully developed 

 rays, since it is very doubtful whether the large pentactines observed in it pro- 

 trude beyond the surface to form a veil, and since ordinary small, not protruding 

 hypodermal pentactines certainly occur in it, I hardly think it advisable to place 

 it in the same genus as this ovoid sponge with its large, freely protruding velar 

 hypodermal pentactines and its pentactine dermals. 



Lanuginella pupa, the only species of Lanuginella, although also differing 

 from Lanugonychia very considerably in shape, resembles it more closely in 

 regard to its dermal and gastral spicules. It is, however, destitute of onych- 

 hexasters, spicules which are very abundant in Lanugonychia flabellum. Ijima ' 



1/. Ijima. Studies on the Hexactinellida. IV. Journ. Coll. sci. Tokyo, 1904, 18, p. 12. 



