REPORT ON THE HEXACTINELLIDA. 225 



rays arc frequently not exactly opposed, but more or less regularly alternating (PI. XXXI. 

 fig. 12), more elongated medium-sized forms also occur, which are sharply distin- 

 guished from the above, by the fact that the umbel is not hemispherical but termin- 

 ally truncate, and furnished with more straightly stretched, obliquely inserted, terminal 

 rays (PI. XXXI. fig. 14). A somewhat smaller form also occurs, in which the umbel 

 rays are not broadened out in paddle-like fashion, but exhibit a narrow point, and in which 

 the axial rod is more or less thickly beset with lateral spines. Finally, the familiar small 

 amphidiscs, with narrow, smooth, axial rods and hemispherical many-rayed (sixteen to 

 twenty) umbels (PI. XXXI. fig. 16), also occur in tolerable abundance, varying in the 

 different regions of the body. In the lowest terminal portion of the body, in the so-called 

 basal pad, strongly developed spicules with six to two rays occur as in all species of 

 Hyalonema. The rounded or truncate ends of the rays are beset with conical teeth or 

 spines, extending to a greater or less distance interiorly (PI. XXXI. fig. 15). 



The long spicules of the basal tuft exhibit spiral or annular, obliquely projecting ridges 

 and rows of teeth, which are inserted on the projecting edge of the ridges. 



There now follow those species of Hyalo7iema, the upper end of which was not 

 sufficiently preserved for deciding the question, whether there is a sieve-plate or not. 



1. Hyalonema lusitanicum, Barboza du Bocage (PI. XXVIII. figs. 12-17 ; 

 PL XXXIX. figs. 16-18). 



The specimen which Barboza du Bocage obtained in the neighbourhood of Setubal in 

 Portugal, and which he described and figured ^ under the title Hyalonema lusitanicum, 

 consisted of a spirally twisted tuft of spicules, the narrower end of which was for a length 

 of 16 cm. and also at the terminal point, completely covered by a continuous layer of 

 Palythoa, while in the longer free portion the spicules diverged in bushy tufted 

 fashion. Neither on this specimen, nor on others which Bocage afterwards obtained 

 from the same locality, could any portion of sponge-body be detected. The following 

 diagnosis was given : — " Hyalonema polypario elongato, fibris setaceis hyaliuis spiral- 

 iter tortis, corio pol}q)igero ad apicem usque ad f longitudinis totius involutis ; 

 polypis dilatatis, ellipticis, valde aggregatis, parum elevatis, per series longitudinales 

 ac spirales regulariter digestis." Barboza must afterwards have found more perfect 

 forms in which the sponge-body was preserved, for I found in the British Museum in 

 South Kensington, London, a spii-it specimen with the label Hyalonema lusitanicum, 

 Barboza du Bocage, and described as a gift from the discoverer. The specimen was 56 

 cm. in length, and exhibited on the much damaged upper end a projecting tuft. 



1 Proc. Zool, Soc. Land., 18C4, p. 205. 

 (ZOOL. CHALL. EXP. — PART LIII. — 1887.) Ggg 29 



