DESCRIPTIONS OF SPECIES. 95 



diverge, the space between adjacent trabeculse becoming' larger. In the 

 intervening space new trabeculse may be introduced. The septal margins, 

 especiaUy in the more exterior portion, are minutely serrate or crenate, the 

 serrse corresponding to the emergence of the trabeculse at the surface. The 

 margins of the interior half (roughly speaking) are so-called entire, i. c, the 

 trabecular terminate in a practically smooth continuous curve. 



Projecting interiorly from the wall are processes that in cross section 

 have the structure of synapticulae — the so-called pseudosynapticula? (see 

 PL VII, fig. 9). The appearance on the side of a septum is shown in PI. 

 VII, fig. 4. 



The columella is composed of several rods that rise upward from the 

 base; they fuse by cross pi-ocesses, and their upper terminations produce 

 the papillate upper surface of the columella. 



There appear to be synapticulse also, formed by the fusion of granules 

 standing opposite each other on adjacent septa. The granules on the septa 

 are long. Those on adjacent septa usually alternate with each other in 

 position; sometimes, however, they stand opposite; quite often they will fuse, 

 forming the so-called pseudosynapticulse. 



This species is extremely close to Trochocyathus cUscoicles Sokolow,' 



so close that after Dr. Sokolow had kindly compared specimens of Tr. 



lunulitiformis with Tr. discoides he wrote me as follows : 



I have from Jekaterinoslaw only a siugle injured specimen of Trochocyathus. A 

 comparison of this specimen with those that you have sent me shows no diflference on 

 the under (outer) side. 1 have also found no differential character in the septa. But 

 the columella of my specimen is somewhat wider thau that of Trochocyathus lunuliti- 

 formis, and the upper surface of the columella of my specimen is more irregularly 

 papillary (warzig); also the pali are somewhat more strongly developed. But as I 

 have only one and that an incomplete specimen, I can not establish that my Trocho- 

 cyathus discoides is without doubt a new species, aud will not oppose placing Trochocy- 

 athus discoides in the synonymy. 



While in St. Petersburg in the summer of 1897, through the courtesy 

 of Dr. Sokolow I had the privilege of examining- the type of his discoides. 

 The septa of his species seem to me thinner than in Tr. lunulitiformis. 

 For the reasons that he has given, and on account of the one I have stated, 

 it appears better to not place his species in the synonymy of Conrad's; 

 but the resemblance between the two is most striking, and ultimately 



' Die unteroligociine Fauna der Glauconitsande bei der EisenbaUnbriicke von Jekaterinoslaw: 

 M«m. (Ill Coinitc GimiIokhi"" (Russia), Vol. IX, Xo. 3. 1894, pp. 92-94, fig. 7 (in test), pi. 1, lig. 5:i-d. 



