Beeclier — Ohservations on the Genus Homing eria, 5 



parent corallites develop tabulae, usually convex, and most 

 numerous within the region of the verticel. In other portions 

 of the corallum they seem to be quite infrequent. Immediately 

 above the row of initial pores there is a tabula in the parent 

 corallite, sometimes showing a number of septal ridges which 

 may correspond to the number of buds and are sometimes 

 continued upward for a short distance as rows of septal spines, 

 figures 3, 4, Plate I. l^o evidence of septa has been observed 

 in any other portions of the corallites in the present collection. 

 The buds before separating usually communicate with each 

 other by one or two mural pores, as shown in figure 6, Plate I, 

 but in no instance except in the initial pore previously men- 

 tioned has a bud within the umbel been seen to bear pores 

 leading into the parent corallite. Also, whenever the corallites 

 of the same or different verticels come in contact away from 

 the whorls, the walls may be perforated by a pore, figure 7, 

 Plate I. 



The examination of a large mass of this coral, measuring 

 nine inches or more in diameter (230™""), shows its almost geo- 

 metrical regularity in a striking degree. It is seen to be com- 

 posed of a number of distinct superimposed horizontal zones 

 or stories, separated by a distance of from 15 to 20"'°". The 

 division planes consist of closely arranged rosettes formed by 

 the whorls of buds given off at regular intervals in the upward 

 growth of the corallum. Betw^een the division planes or from 

 the floor to the ceiling of each story are to be seen the simple 

 columns of the individual corallites with their Corinthian-like 

 capitals, which are to develop into a verticel of daughter coral- 

 lites at the division plane above, Plate lY. 



In a large corallum, each umbel of thirteen corallites (one 

 parent and twelve buds) generally occupies a space of about 

 lYO square millimeters. The size of this area was determined 

 by enumerating the umbels occurring in several areas measur- 

 ing 60 X 50™"^. The average showed fifteen umbels for this 

 space, containing in the aggregate one hundred and ninety-five 

 corallites. 



One specimen measuring 100 x 200°^"" on the horizontal sur- 

 face has approximately 1500 corallites on each zone. Three 

 zones are complete for the same area and together contain 

 about 4500 corallites. Now if each of the 1500 corallites of 

 the bottom zone gave origin to twelve buds the next zone 

 would contain 19,500 corallites, and the same process would 

 demand 253,500 corallites for the third zone. This shows a 

 suppression of 243,000 corallites on two zones. 



The suppression of corallites seems to be due principally to 

 two causes : {a) The crowding of the umbels together in the 



