238 



ous alga, on the ground that "no recent coelenterate has zooidal tubes 

 as minute, or nearly as minute, as those of Solenopora. Its structure 

 is," he says, "truly cellular and not tubular." In the same paper. Pro- 

 fessor H. A. Nicholson is quoted as saying : " We cannot refer it to the 

 Hydrozoa, for we are not acquainted with any hydrozoon, living or 

 extinct, with which Solenopora could be compared. It shows no features 

 in its minute structures which remind us of the hydrocorallines, and it 

 assuredly presents no structural resemblance to any known type of the 

 Stromatoporoids." 



Ch^tetes perantiquus. (N. Sp.) 



Fig. 17. 



Fig. 18. 



Figs. 17, 18 and 19. Chcetetes perantiquus. — Fig. 17, transverse section of part of 

 the specimen described, close to the surface and above the uppermost 

 ^ transverse diaphragm, XIO; fig. 18, transverse section of part 



of the same specimen, lower down and below the upper- 

 most diaphragm, X16; and fig. 19, longitudinal 

 section of a part of the same, XIO. 



Corallum, as indicated by a single and imperfect specimen, forming a 

 large undulating expansion or crust, which is slightly and irregularly 

 convex above, shallowly and irregularly concave below, and from three 

 to seven millimetres thick. Corallites of one kind only, in complete 

 contact throughout their entire length, and averaging a little more than 

 half a millimetre in their longer diameter, and a little less than half a 

 mm. in their shorter. As seen in transverse sections near the surface, 

 such as that represented by fig. 17, the corallites are variable but for 

 the most part nearly oval or almost circular in outline, with a depressed 

 space or groove round each, and with single minute interspaces between 

 them. The two features last named, however, are purely superficial, for 



