Rev. T. R. R. Stebbing on neio Crustaceans. 95 



its surface giving it exactly the appearance of an undulating 

 plain covered with numerous small volcanos. Superficially 

 examined, it presents a striking resemblance to many recent 

 sponges ; but I have not been able to satisfy myself that the 

 conical elevations just alluded to are really of the nature of 

 oscula. Some of them certainly look as if they were perforated ; 

 but most show no signs of any aperture. This maybe due to 

 the manner in which the fossil has been preserved ; but I can- 

 not speak positively upon this point. The internal structure 

 of all the examples wliich I possess of this species is much 

 more imperfectly preserved than is the case with the othei 

 species here described, and I have simply been able to satisfy 

 myself that it is essentially the same as is characteristic of Stro- 

 matopora in general. I have seen crusts of this species covering 

 an area of several square feet ; but it is by no means common 

 in its occurrence. 



Loc. and Form. Rare, in a silicified condition, in the Cor- 

 niferous Limestone (Devonian) of Port Colborne, on the north 

 shore of Lake Erie, Canada West. Collected by the author. 



5. Stromatopora concentrica, Goldf. 

 Besides the preceding three species I have found in the 

 Corniferous limestone of Canada specimens Avhich are un- 

 distinguishable from 8tromatopora concentrica^ Goldfuss. As^ 

 however, none of these specimens exhibit their surface it cannot 

 be positively asserted that they belong to this familiar Devonian 

 species. 



EXPLANATION OF PLATE IV. 



Fuf. 1. Fragment of Stromatopora ostiolata, Nich., natural size. 



Fig. 1 a. Fragment of the same, enlarged, to show the oscula on the 



sui'face. 

 Fig. 2. Fragment of Stromatopora tuberculata, Nich., natural size. 

 Fig. 2 a. Lateral view of a fragment of the same, enlarged, to show the 



reticulate structure. 

 Fig. 3. Fragment of Strotnatopora granulata, Nich., natiu-al size, showing 



the granulated surface. 

 Fig. 3 a. Lateral view of a fragment of the same, enlarged to show the 



reticulate structure. 

 Fig. 4. Fragment of Stromatopora inammiUata, Nich., natural size. 



XII. — A Sph(B7'omid from Australia, and Arcturidffi from 

 South Africa. By the Rev. Thomas R. R. Stebbing, M.A. 



[Plate III. A. figs. 1-3 a.] 



The crustaceans described in this paper presented themselves 

 among the sand and fragments shaken in transit from a variety 



