DESCRIPTIONS OF SPECIES. 97 



This species, as well as Tr. lunulitiformis (Conrad), should be compared with 

 Tr. discoides Sokolow, from Jekaterinoslaw, southern Russia. 



Oue of the type specimens of the Tr. caUfornianus shows an interesting 

 feature, probably an abnormality. Apparently a bud is being formed from 

 the calicinal region. PI. VII, fig. 13, represents the condition. 



Trochocyathus depeessus sp. nov. 

 PI. VII, figs 14 to 17. 



Form subdiscoid, or bowl-shaped; transverse outline subcircular, 

 slightly irregular. Base convex, calice wide open and moderately deep. 

 There is no sign of attachment, although the base is disfigured in eight of 

 the nine specimens that I have examined. Costee corresponding to all cycles 

 of septa not very prominent, but distinct to the base. In size they are sub- 

 equal ; every fourth is usually slightly more pi'ominent than the three inter- 

 vening. They are slightly acute, and along the crest is a single series of 

 granules. Their sides 'ilso are granulate. 



Septa numei'ous, about 80. The arrangement is extremel}' difficidt to 

 make out, as the primaries and secondaries are of the same size. They pro- 

 ject very slightly above the upper margin of the wall. The free margins 

 of the septa, after rising a little above the wall, lie in a horizontal plane for 

 about one-fourth the diameter of the calice; then they fall to the bottom of 

 the calice in a curve parallel to the corallum wall. The}' are considerably 

 thicker near the wall. The sides are highly ornamented. The pattern of 

 ornamentation is extremely complicated. It is shown in PI. VII, fig. 16. 

 Two zones of different kinds of ornamentation can be recognized. An 

 outer, in which there are projections from the corallum wall. Between 

 these projections are small, closely crowded granules They are arranged, 

 in not very distinct rows, subparallel to the upper margin of the septa 

 at the wall and to the processes extending inward from the corallum wall. 

 The second zone consists of elongated granules that slope upward and 

 inward, making an angle of approximately 45° with the septal margin. 

 The general scheme is very well represented in PI. VII, fig. 16. The 

 interpretation of this arrangement of granules is that there is a line of 

 trabecular divergence along a line extending lengthwise just about the 

 middle of the septum; above this line the trabeculse are directed upward 

 (i. e., inward); below they are directed outward or downward (morpho- 



MON XXXIX 7 



