GENERA OF FAVOSITJD.E. 163 



plete. When the corallites are not in contact, the space be- 

 tween them is filled with a variously-formed vesicular tissue. 

 This genus resembles Heliolites, but differs therefrom in having 

 double the number of septa and the w^alls perforated." 



Two species were described by Mr Billings as belonging to 

 this genus — viz., C. Canadensis, from the Black River Lime- 

 stone, and C. Hnroncjisis, from the Hudson River formation. 

 The former is stated to have corallites about one line in dia- 

 meter, and generally in contact, although still remaining cir- 

 cular ; while the mural pores are arranged in horizontal rows 

 running all round the tube, one row between each pair of tabulae. 

 The latter was separated specifically from C. Canadensis, prin- 

 cipally upon the ground of the greater slenderness of its tubes. 

 Neither of these forms was figured. From the above descrip- 

 tion it would appear that Calapoecia Canadensis and C. Huj^on- 

 ensis are corals nearly allied to the form which I have de- 

 scribed as Colwnnopora cribri/ormis ; but such a conclusion has 

 been rendered very hazardous by the publication by Mr Bil- 

 lings, at a later date, of a third species of Ca/apcecia, which was 

 both described and figured (Cat. Sil. Foss. of Anticosti, p. 32, 

 fig. 15, 1866), The species in question (viz., C. Anticostiensis) 

 is stated to have a hemispheric corallum, the corallites some- 

 times in contact, but usually distant from one another by a 

 quarter or half a line. The shape of the corallites is circular, 

 and they are surrounded on the exterior by a fringe of well- 

 developed costcB, while the spaces between them are subdivided 

 by horizontal and close-set exothecal plates. The septa have 

 the form of longitudinal striae, and tabulae were only obscurely 

 seen. In a note Mr Billings adds that this species would seem 

 to be congeneric with Syri^igophyllwn organ7im. 



Whether or not Mr Billings be correct in the suggestion just 

 alluded to, the above description and the figures which accom- 

 pany it leave no doubt whatever as to the entire distinctness 

 of Calapoecia Anticostiensis, Bill., and ColiLvmopora cribri/ormis, 

 Nich. If, therefore, the originally-described species — viz., Cala- 

 poecia Canadensis and C. Htironensis — are to be regarded as 



