no 



UOYAL SOCIETY OF CANADA 



beds cxploi-cd at Metis, and iiKtst of them have Ik-cii luudi lii'dken ii|». 

 Only one speciinon was obtained in a toicniMe state of completeneHs. 



For further rernai'ks on the strueture and affinili«'s of this sponge liv 

 Dr. llitide, see tlie paper of 1S81>. 



(Jenub ACANTHODICTYA. Himlr. 



Kponj^es approximately siiheylindrieal in forni.jeoiisiHtinsj: of a skeletal 

 mesh-work of loni^itudinal and transveiNe spieular strands or fibres. The 

 lon<;iludinal strands are composed of somewhat loosely ari'anncfl fascieles 

 of elongated overlappinff s])ieules. and I la; sj»i(ules (d' the slender trans- 

 voi"so fibres are as a rule disposed in a siuifle series. From the outer 

 surfaee of the sponge, numerous spicular rays ])rojoet outwards at I'iii'hl 

 an«;les. The spony-e a]»pears to have been anchored by a basal prolony- 

 ation of the longitudinal strands. Owin^ to the present c^)mpressed 

 ecmdition of the s]>e(imens it is dittieult to determine the original form 

 of the constituent spicules. Some of the elon<;ated Icmgitudinal spicules 

 may be merely simj)le i-oddike forms, others are clearly cruciform and 

 their transveree rays form the cro.ssfibres. The spicuiai- rays of the 

 ])rojectinfr bristles of the surface may be the free distal rays of normal 

 hexaetinellid spicules, but only these projecting rays can now be clparly 

 distinguished ; the (jthers are merged in the longitudinal fascicles. 



The general structure of the skeleton resembles that of Cijathophyous. 

 Waleott, but it is characterized by the })resence of the projecting surface 

 rays. The mesh is also of a looser character than in Cyathophycus and 

 its arrangement in quadrate areas is only faintly i-ecognisable. 



!». — AcANTHOniCTYA HISl'IDA, HiluJc. 



(Figs. 20 and 21. PI. III., Fig. 11.) 



21.—Acanthodictyn /u'sjatrffr.— Portions enlarged x 

 showing frninework and cruciform and 

 protective spicules. 



o, 



Fig. ^.—Acanthodictya 

 hispida. Restored. 



