520 Revieivs — H. Rauff—Oii ReceptacuUtes 



come in contact with each other, and form an inner or upper wall to 

 the cup. In E. occidentalis, from Canada, this inner wall has been 

 shown by Billings and Hinde to be regularly perforated by canals 

 which communicated with the spaces between the pillars ; but Dr. 

 Rauflf asserts, without having seen the Canadian specimens, that the 

 perforations are only secondary, and not original ; and that the inner 

 wall is not penetrated by canals. But as far as can be judged from 

 the author's figures of the inner wall of B. orbis (pi. iii. figs. 10, 

 10«; figs. 3, 4, p. 675), similar perforations are presented in it as in 

 the Canadian species, and in this latter they are too distinct and 

 regular to be explained away as produced by fossilization. 



The author shows that the meridional arms of the spicules in 

 Beceptaculites, and possibly throughout the group, follow a very 

 regular arrangement, whereby the arm directed to the nucleus or 

 commencement of growth (proximal, Hinde ; distal, Raufi") is tilted 

 obliquely towards the outer surface, whilst the opposite arm points 

 obliquely towards the interior of the organism. 



Dr. Raulf considers that when complete the summit or upper end 

 of IscTiadites was completely closed, in spite of the fact that in all 

 the specimens yet known in which the upper portion is preserved, 

 there is a small aperture which communicates with the inner cavity. 

 This apertural fact is attributed to subsequent injury in fossilization, 

 or to artificial enlargement, by those who have studied and figured 

 the specimens ; but it may be noted that the existence of this 

 summit aperture seems never to have been questioned pi-eviously. 

 In another point the author differs from previous observers who 

 have shown that the pillars or vertical rays in good specimens of 

 Ischadites Koenigii gradually taper to a point, and do not form an 

 inner wall ; but as a fragment of a poorly preserved drift-specimen 

 shows trumpet-shaped inflations, the author concludes that these 

 were the original terminations in this species, and explains the 

 spicules with pointed ends as arising from subsequent alteration ; 

 but this explanation will certainly not account for the tapering 

 spicular rays in some of the Gotland examples of T. Koenigii, which 

 show every indication of being complete. 



Dr. Rauff refers to Leptopoterion, Ulrich, as a new genus of this 

 family, characterized by the nearly uniform diminutive size of the 

 summit plates of the spicules. The form has not yet been figured, 

 and the only species has been described as a sponge. 



In a promised future Supplement the author intends to describe 

 the various species, and it is then to be hoped that he will be able 

 to definitely settle some of the doubtful structural points, and at 

 the same time bring forward some positive conclusions as to the 

 systematic position of this peculiar family. 



Some fresh information respecting the structure of Splxerospongia 

 tessellata, Phill. sp., based on specimens from the Devonian rocks on 

 the shoi'es of Lake Manitoba, is given in a recently issued part of 

 vol. i. Contributions to Canadian Palagontology, p. 259, pi. xxxiii. 

 The summit in this species is stated to be formed by the convergence 

 of the prolonged distal rays of the upper spicules in each longi- 



