no 



UOYAL SOCIKTY OF CANADA 



1)0(|8 oxplorod at Mi^tis, imd most of tlioni liiivc Iwcii imuli hrokt-n up. 

 Only (mo Hpocimon wuh ohtained in a (olcrahlc stato of'cdinpkitonoHs. 



For furtluT iTiuurkH on the Mtructun' and afflnitit'Mof tliis Hpoij^c by 

 Dt. """'.ndo, 800 tho paptT of 1H89. 



(JENirs AOANTIIODICTYA. Hitu/r. 



SpoTi^os ny)]»roxin>atc'y Hiilicylindrical in fbnn.jcons' ■•; ofa ukolutal 

 mosli-work of longitudinal and transvoi-Hc spioular stranob .>r "hrcs. The 

 longitudinal Ht rands arc composed of soinowliat loosely a "ran/' I faseicles 

 of eloni^ul'id ovevlappin;; HpimU'H. and the Hj)ic»;leH of tl-e Hienu. r tnins- 

 voive fibroH a''e as a rule diHpoMed in a Hinijjle Hcvies. Fvi-m the outer 

 surface of the spon/re, numerous 8]>icular rays project outwards at ri/^ht 

 angles. The sponife a])pearH to have heen ancliored hy a hasal prolong- 

 ation of the lon/^itudinal wt rands. Owin^ to the present con)])re8sed 

 condition of the H)>e(Mmens it is ddticult to determine the original form 

 of the ct)n8tituent 8|)icule8. Some of the olontjated lon/^itudinal 8])icules 

 may bo merely sim])le rod-like forms, others are clearly cruciform and 

 their transverse rays form the cross lihres. The spicular rays of the 

 ])rojectin^ I)ri8tles of the surface may he the free distal rays of normal 

 hexactinollid spicules, hut only these projectin/j; rays can now be clearly 

 dlstin/ijuishod ; the othei-s are merged in the longitudinal fascicles. 



The general structure of the skeleton resembles that of Ci/athophycus, 

 Walcott, but it is characterized b}' the presence of the pnjjecting surface 

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

 its arrangement in quad i ate ai-eas is only faintly recognisable. 



9. — AOANTHODICTYA HI8PIDA, HindC. 



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



Fig. 21.— Acanthodicfya hispidn.— Portions enlarged x 5, 



showitiK framework and cruciform and 



protective spicules. 



Fig. 20.—Acant/iodictt/a 

 hispida. Restored. 



