• 82 



recurved, crosswise-arranged anctor-teetli, 20 M long, arise. The axial cross lies 

 in the terminal thickening, close to the bases of the four teeth which are there- 

 fore probably to be considered as true rays and not as mere enlarged spines. 

 Whether these anchor-spicules serve to attach the sponge to the sea-bottom 

 cannot be decided on account of the fragmentary condition of the specimen. 

 It is certainly probable that spicules of this kind, but of much larger size, 

 protrude from the basal part of the sponge and form an anchoring root-tuft. 



Placopegma solutum was found in the central part of the Bay of Bengal 

 12^ 50' N., 90° 52' E. in a depth of 3008 m. = 1644 fths. 



LOPHOCALTX F. E. Sch. 

 Lophocalyx spinosa F. E. Sch. 

 Plate XXIII. 



1900 Lophocalyx spinosa F. E. Soil, in Abh. Preuss. Ak. 1900 pp. 35-39 Taf. VII. 



The only specimen of this sponge consists of an irregular, round mass, 3-4 cm. 

 in diameter, with a large, strongly curved, cylindrical, handle-like, digitate 

 process so bent round, that the distal part extends nearly parallel to the central 

 body of the sponge. Part of the surface is simply convex and smooth, the other 

 part, from which the large process arises, is tuberculous. An equatorial groove 

 partly bounded on one side by a projecting ridge, divides these differently formed 

 parts of the surface from each other. From this limiting, marginal ridge and 

 from the protuberances of the tuberculous region numerous straight or slightly 

 curved spicules, about 100 a^ thick, protrude singly or in small bundles for a 

 distance • of 2-3 cm. beyond the surface (pi. XXIII, f . 1, 2). Most of these 

 prostalia-spicules are broken off; the few intact ones are either gradually 

 attenuated and simply pointed or terminate with tetradentate anchors. There is 

 no distinct oscule, but there are a few roundish apertures, 2-3 mm. wide, with 

 "smooth margins in the equatorial groove, and some small, scattered openings 

 covered by the superficial membrane, which can be considered as excurrent 

 apertures. In the interior, a system of cavities, 3-4 mm. wide, is observed, 

 which doubtless form part of the excurrent system. 



Since the shape of the body and the arrangement of the protruding spicules 

 resemble those of some species of Thenea I think it justifiable to suppose that 

 the natural position of this sponge is similar to that of those Theneas, that is to 

 say that the smooth, convex part of the surface is its upper and the tuberculous 

 part its lower side. The prostalia protruding from the tubercles of the latter 

 would accordino"ly have to be considered as root-tuft-spicules, anchoring the 

 sponge to the sea bottom. 



The macrosclere, parenchymal principalia are oxydiactines. They traverse 

 the body, singly or in bundles, in different directions, chiefly however parallel 



