426 G. HERBERT FOWLER. 



differentiation of the mesenteries is similar, though perhaps 

 hardly so well marked as in the other species, since the mesen- 

 teries numbered 3 and 10 in the diagram of P. brevicornis 

 are often not appreciably longer than 5 and 8. The reticular 

 tissue mentioned as filling in Seriatopora subulata and 

 P. brevicornis the spaces from which corallum has been 

 removed by decalcification, is in this species very much more 

 clearly recognisable. It appears to consist of thin strauds of 

 (?) protoplasm (? mesoglcea), staining deeply with carmine ; it 

 retains the shape of the crystalline ellipsoids of which the 

 corallum is ultimately composed, and forms an accurate cast 

 of the dead internal parts of the colony. 



Seriatopora tenuicornis, sp. n. (figs. 14, 15). 



For a small fragment of a colony of this species I owe my 

 thanks to Dr. S. J. Hickson, who collected it with other corals 

 in the Celebes group. 



In anatomy this form agrees exactly with the Seriatopora 

 subulata, already described (" Anat. Madr./' iii). It appears 

 to constitute a new species, of which the following are the 

 diagnostic characters: — The branches are thin and finely 

 tapering, exhibiting no tendency to unite in the manner cha- 

 racteristic of most Seriatoporse ; they are very solid in section, 

 and bear four or five rows of calyces. The coenenchyme is very 

 regularly ribbed, the echinulations of which the ribs are 

 composed being markedly short and blunt. The calyces pro- 

 ject slightly above the surface of the coenenchyme ; the septa 

 are generally about ten in number, short, and very irregular. 

 The columella does not reach to the surface of the calyx; it 

 is spinous, and not so plate-like as in some other species of the 

 genus. 



From S. caliendrum, to which it is approximate, it differs 

 in that the calyces are farther apart, and project more from the 

 coenenchyme than in that genus ; the echinulations are further 

 apart, blunter, and shorter ; the branches more slender. The 

 specimen has been deposited in the British Museum. 



