69 



place where the side-branches commenced, a little Area pectunculoides was attached to the 

 stem by its byssus (a). 



By its highly characteristic form, and peculiar attachment, this sponge differs from 

 all other known forms. ' The arrangement of the central spicula in close axial fascicles, from 

 which again radiate other smaller fascicles in the single processes, seems to shew that it 

 must be more nearly referable to the 1'.' of the gi'oups of siliceous sponges, established by 

 Bowerbank, and characterised by a spiculo-radiate skeleton. Of the genera belonging to this 

 group, the genus Hymedesmion is that, which in respect of the structure of the superficial 

 retentive spicula, appears to approach it most closely; but the species of this genus are of 

 a quite different form, namely consisting of thin crusts over extraneous bodies (shell &c.). 

 It exhibits moreover some conformity in the structure of the spicula with the genus Dcs- 

 macidon, which belongs to quite another group, distinguished by a spiculo-fibrous skeleton. 

 The form is however here entirely different; and the skeleton cannot either be properly called 

 fibrous; unless the whole sponge can be considered as one single ramified fibre. 



The genus may be characterised in the following manner. 



Gen. Cladorhiza. M. Sars. 



Spongia silicea ramosa, fasciculis densis spiculorum acuformium axem solidam forman- 

 tibus sustentata, radiculis numerosis arborescentibus ex spiculis ejusdem generis formatis in 

 limo affixa. Parenchyma axem internam corticis instar circumdans spiculis superficialibus 

 auchoratis et bihamatis ornatum. Oscula et pori nulla. Ova in apicibus dilatatis ramorum 

 se evolventia. 



Spec. Cladorhiza abyssicola. M. Sars. 



Spongia ex stirpe composita tenui erecta ad basin in fibrillas radicales numerosas 

 arborescentes se dividente, de cujus parte superiore exeunt undique radiantes rami laterales 

 simplices, recti, latitudine eadem ac stirps ipsa et apice tumefacto terminati. Stirps in tota 

 fere longitudine et rami processibus numerosis suba^qualibus attenuato — conicis, subarcuatis, 

 lateraliter compressis, fasciculis spiculorum centralium sustentatis circumcirca ornata. Paren- 

 chyma axem spiculosam ubique (radiculis exceptisj investiens. simplex, sine lacunis intersti- 

 tiisve, membrana vero ornatum externa distincta spiculis numerosissimis minimis ina^qualiter 

 anchoratis in processibus conicis imprimis dense accumulatis instructa, inter qua; obveniunt 

 alia multo majora bihamata sparsa in apicibus ramorum tamen frequentiora et cum illis hie 

 etiam spicula alia multo tenuiora bihamata sed hamulis in directiones diversas vergentibus 

 insignia. Ova (vel gemmulse) magna spiculis omnino carentia in parenchymate ramorum et 

 stirpis libere accunuilata. Color dilute pallide-fulvus. Altitudo speciminum maximorum 60 

 Mm., latitude stirpitis et ramorum 1 Mm., longitudo processuum secundarium 3—5 Mm. 



Habitat rara ad insulam Lofotensem Skraaven in profunditate 300 orgyarum fuudo 

 argillaceo. 



