DESCRIPTIONS OF SPECIES. 145 



The septa are composed of extremely narrow ascending trabeculte, 

 which are only 0.02 nnn. or sUghtly more across. The trabecule are crossed 

 by transverse undulations, and very often a considerable number of dark 

 points in the trabecular indicate the position of the undulations. These 

 dark points apparently are calcification centers. A line of divergence was 

 not observed; all of the trabeculse within the wall pass upward and inward. 

 No section of the extra-mural portion of the septa that could be studied 

 was obtained; so there may be, and probably is, a line of trabecular 

 divergence. 



The wall. — The walls of the corallites of the central part of the colony are 

 thin. When the middle lines of the septa are dark, a small, dark, circular 

 line joining the septa together, is seen in the wall; when the median septal 

 line is light, a light line is seen in the wall. I was unable to recognize dis- 

 tinct calcification centers with certainty in the wall, but it seems that the 

 wall originally belongs to the true thecal type. In corallites, when the wall 

 has been secondarily thickened from the outside, the same circular line can 

 be distinguished near the corallite cavity, but outside of this the fibro- 

 crystals converge inward to the costal axis, presenting the appearance of a 

 pseudothecal wall. (PI. XVI, fig 3.) 



REMARKS. 



The systematic position of this coral is very puzzling. It certainly 

 has nothing to do with what were considered the representative genera of 

 the Astreidse (Mussa, Orbicella, etc.). It shows more features in common 

 with the Oculinida?, but we do not understand the Oculinid structural char- 

 acters sufficiently well for the relations with that family to be discussed 

 intelligently; therefore at present it is given no family association. 



Haimesiastr^ea conferta sp. nov. 

 PI. XV, figs. 6 to 9; PI. XVI, all figures. 

 Colony rather massive, ramous. Corallites crowded together, rather 

 shallow, subhexagonal in outline; caUces circular, 1.5 mm. in diameter; the 

 margins project very slightly above the rather dense coenenchyma. The 

 coeneuchymal walls between the calices frequently 1 mm. thick on the older 

 portions of the colony. Costte distinct, corresponding to all cycles of the 

 septa, granulate. The costse of one calice meet those of the adjoining calices. 

 The line of the junction usually indicated by a delicate ridge. The whole 



MON XXXIX 10 



