INDIAN AND PERSIAN flONIOPOR^. 95 



67. Goniopora Sind (1^)6. 

 [A pebble probably from near Kurrachee, Sind (Eocene), British Museum.] 



Description. — The corallum massive. 



The calicles small up to 2 mm., polygonal, with distinct walls which may have been sharp 

 and zigzag at the growing surface, but in transverse section are coarse and irregularly 

 thickened, and perforated. The intracalicular skeleton seen in the sections is peripherally a 

 confused reticulum, and might be taken for tliat of Porites ; for where the radial symmetry is 

 best shown 12 short rays arranged round a variously developed, usually slight columellar 

 tangle form the most conspicuous feature, but peripherally these septa branch and run together 

 to form a network with rounded meshes. It would be easy to mistake this network in many 

 of the calicles for a thick reticular wall, in which case the coral would be a Porites with 12 

 septa. In others, however, the branching septa look like the ordinary fusing of the tertiaries 

 with the secondaries in Goniopora. Without knowing what the walls were like at the original 

 surface, no certain conclusion can be arrived at. I feel justified, however, in assuming that the 

 zigzag lines still persisting and seen in the section formed the true wall at the surface,* and 

 that the skeleton contained within them was at the surface clearly septal. The confused 

 reticulum seen in the section is perhaps due to development of synapticulie and thickening of 

 the elements such as is common in the basal part of calicles. 



My view, viz. that the coral was a Goniopora and not a Porites, is further confirmed by 

 the presence of the columellar tangle almost unknown in Porites, and by the absence of all 

 traces of the septal formula of Porites. Cf the origin of Porites from Goniopora in the 

 Introduction, p. 21. 



In contrast with the general thickening of the walls and septal elements, the columellar 

 tangle remained a delicate open sponge-work. 



There is one pebble, whicli is of a light greyish or brownish pink colour, and a micro- 

 scopic section. 



T> 04. 



«• Geol. Dept. -^^ transferred from India Museum, London, 1880. 



68. Goniopora Sind (7)7. 

 [Pebbles probably from near Kurrachee (Eocene), British Museum.] 



Description. — Corallum massive. 



Calicles, seen only in section, about 2 mm. across, and separated by reticular walls 1 mm. 

 thick. The walls are a close reticulum of stout threads of nearly uniform thickness ; they 

 show no traces nf any median strand which at the surface could have formed a sharp ridge 

 zigzag or straight, such as can be seen in the last specimen. Hence the walls at the surface 



* Cf. the structure of the wall in the next form, G. Sind 7. 



