274 THE VOYAGE OF H.M.S. CHALLENGEE. 



another. Among the free spicules which are present in the soft parts, and are especially 

 abuudnnt in the skin, Bowerbank notes simple hexradiate spiciiles, with smooth or finely 

 fringed rays, and also floricomes, with small terminal plates on each of the four 

 S-shaped terminal rays of every principal ray. Bowerbank notices the great resemblance 

 between this species and Farrea occa, but he at the same time calls attention to some 

 small differences, such as the slightly roughened surface of the beams of the network, the 

 slender form of the teeth, and the peculiar floricomes. 



Of Farrea aculeata, Bowerbank, the author possessed only a fragment, the form of 

 which pointed to a cup-like form for the animal. The usually two-, more seldom three- 

 layered lattice-like framework consists of strong, canaliculated, siliceous beams, which 

 surround tolerably regular square meshes, and are irregularly beset with conical prickles 

 and thorns of various sizes. Here and there hexradiate spicules which have grown 

 upon the above also occur. This species has a striking resemblance to Farrea spinifera, 

 as Bowerbank himself recognised. 



The skeletal framework of Farrea robusta, Bowerbank, has a close resemblance to 

 that of Farrea aculeata. It differs from it strictly only in the greater size of the beams 

 and in the corresponding narrowness of the square meshes, as also in the greater 

 thickness of the fully developed rough hexradiate spicules — differences which everywhere 

 occur between older and younger parts of the same sponge. The soft parts and 

 IMonactinellid spicules found by Bowerbank in the framework are quite independent, and 

 belong to a Desmacidonid which had settled in the skeleton after the death of the 

 Hexactinellid. 



Another fragment of a siliceous framework with several lattice-like layers, and provided 

 on lioth surfaces of the somewhat bent plate with meshes which are uniformly square 

 but more irregular in the interior, Bowerbank has named Farrea inermis, because the 

 beams are entirely or almost entirely smooth. From the knots of the network slender 

 smooth teeth project at right angles. Similar prickles also project here and there into 

 the inner meshes. 



Bowerbank has designated as Farrea perarmata a flat, slightly bent, skeletal fragment 

 in which the framework of beams, which forms square meshes, is everywhere richly beset 

 with spines and prickles of various sizes, and exhibits no recognisable central canals. 

 Long rough conical teeth project outwards and inwards. Numerous thorny hexradiate 

 spicules also occur with one ray in each directed at right angles to the beams of the 

 network. 



Another bent skeletal fragment, consisting of a tolerably irregular framework 

 of beams which here and there exhibit square meshes, Bowerbank names Farrea 

 irregularis. The individual beams have a very varied thickness, and for the most part 

 perfectly smooth, isolated, small hexradiate spicules also occur. 



If we review these fourteen species established by Bowerbank during the years 



