INDIAN OCEAN PORITES. 2/9 
The single specimen at one time enveloped the top of an Astrid coral. The small 
size of the calicles differentiates it from the next form. Both are alike in having reticular 
walls, and conspicuous rings of pali; and, again, neither seem to have originally adhered to 
any firm base. This one grew upon a coral, and the next upon fragments apparently of 
organic origin, which allow the coral to topple over when it gets at all heavy. 
Briiggemann’s identification of it with Porites lutea of Milne-Edwards, which included 
Quoy and Gaimard’s coral from Tonga, and others from the Red Sea, was not based upon any 
close study of Milne-Edwards’ specimens (see above, p. 34, and below, p. 244). 
a. Zool. Dept. 76. 5. 5. 45. 
226. Porites Rodriguez (2. (P. Rodericensis secunda.) (Pl. XXXII. fig. 5; 
Pl. XXXYV. fig. 28.) 
[ Rodriguez, coll. Transit of Venus Expedition ; British Museum. | 
Syn. Porites wrenosa * Briiggemann, Phil. Trans., clxviii. (1879) p. 577. 
Description —The corallum grew upon a loose organic fragment, and as it increased in 
size it rolled over. From its side a new stock rises upwards and swells into a knob, with a 
short, thick stalk. The stock is thus roughly dumb-bell shaped, the smaller distorted and 
corroded knob forming the base, from which the larger and more symmetrical recent colony 
rises. The edge is closely adherent, and bends under. 
The calicles are conspicuous, 1 mm. in diameter, varying rapidly from angular to sub- 
circular, The walls vary suddenly and apparently arbitrarily from being thin, straight and 
membranous, to an irregular reticulum ; the walls of adjacent calicles or even parts of one and 
the same calicle may vary; and, when reticular, there are no traces in the coarse open mesh- 
work of a median ridge corresponding with the membranous walls elsewhere. The septa are 
thin and membranous, sometimes smooth, at others with a few echinulations, without septal 
granules, but with a conspicuous oval ring of plate-like pali in the complete formula. The 
flattened columellar tubercle forms a conspicuous line with the directives, while deeper down 
there is a compact round columellar tangle very conspicuous in cleaned specimens, because of 
the ring of large, round, interseptal loculi. 
There are no available sections, and the colour seems to have been a warm buff. 
There are two specimens, exactly similar in growth-form. 
In the larger specimen (a) the calicles are larger, and the skeletal elements are slightly 
thicker and echinulate; in the smaller specimen (b) the skeletal elements are very thin and 
delicate. 
a, b. Zool. Dept. 76. 5. 5. 44. 
* On the label Dr. Briiggemann wrote Porites arenacea Lamarck ; Esper wrote “ arenosa.” 
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