REPORT ON THE MONAXONTDA. 123 



Spicules. — (a) Megasclera; doubtful. {h) Microsdera; two kinds are present. 

 (1) Very numerous palmate anisoclielse of the characteristic lophon type, 0"0145 mm. 

 long ; these sjsicules are frequently arranged around the walls of the canals, with 

 the small end sticking into the wall and the larger end projecting into the cavity. They 

 also occur very abundantly in the dermal layer. (2) A very few small bipocilli (? foreign). 



It is, of course, very difficult, amongst such a number of foreign spicules of almost all 

 sorts and sizes, to pick out just the ones which are proper to the sponge itself ; hence it 

 is with some hesitation that we refer this species to the genus lojyhon. 



The most abundant spicules, and those which are most certainly proper to the sponge, 

 are the auisochelse. The sand grains occur chiefly in the deeper parts of the sponge. 

 They appear to be arranged, together with the other foreign bodies, without any definite 

 order, and to take the place of the proper megasclera. The figure (PI. XVII. fig. 10) 

 will give some idea of the arrangement of the foreign bodies — chiefly sponge spicules — 

 in the dermal layer. 



In its collecting habit this sponge agrees closely with Marshall's Phoriospongia,^ 

 and it seems to us very probable that individual species out of several distinct genera 

 have acquired the same habit of replacing their proper skeleton with a skeleton of 

 foreign bodies. This is sufficient to distinguish the species unmistakably from all 

 others as yet known of the genus lopTion. 



Locality.— Qtsition 163a, April 4, 1874 ; lat. 36° 59' S., long. 150° 20' E.; ofi"thc south- 

 east coast of Australia ; depth, 150 fathoms; bottom, green mud. One small specimen. 



Genus Amphilectus, Vosmaer (Pis. XIX., XXV., XLVIL). 



1880. Amphilectus, Vosmaer, Notes from the Leyden Museum, vol. ii. p. 109. 



We make use of this genus in the manner indicated by its founder, namely, as a 

 provisional receptacle for a number of doubtful Desmacidonidse (Esperellinse). 



As regards the diagnosis and history of the genus we quote Vosmaer's later remarks 

 on the subject.^ " Stabnadeln glatt oder (und) gedornt. Dazu Anker oder (und) 

 Schaufeln mit gleichen oder ungleichen Enden ; eventuell auch Bogen und Haken. 

 Sponginmasse sehr wechselnd. Kosmoj^olitisch;" this, of course, would include jjretty well 

 every species of Desmacidine, and Vosmaer continues: — " Es ist Amphilectus nur ein 

 vorlaufiges Aushilfe-Genus, wo alle diejenigen Desmacidinen untergebracht sind, von 

 welchen keine besondere Merkmale bekannt sind, wodurch sie zu einer anderen Gattung 

 kommen soUten." As such we accept it, but we have not made it quite so comprehensive 

 as Vosmaer has done, and we include in it here only such Esperellinfe as possess 

 isochelate microsdera and (usually) stylote megasclera, to which other forms of spicules 



1 Zeitschr.f. wiss. Zool, Ed. xsxv. p. 122. " Bronn's Klass. u. Ordn. des Thierreichi?, Porifera, 1885, p. 353. 



