16 MADREPORARIA. 



specimen from Singapore as "Rhodarcea lagreneii," and further identified it with the coral 

 figured by Savigny, Desc. de l'Egypte, pi. 4, fig. 6, called Porites clavaria* 



Professor Studer followed Briiggemann in including a " Rh. lagreneii " among the 

 Singapore corals and stated that he had found a similar " species " in New Ireland. 



The position assigned by Martin Duncan to this genus has already been mentioned above 

 in the history of the genus Goniopora, where mention is also made of the references to the 

 genus by Mr. Saville-Kent. 



See also under same heading for the results of the • Challenger ' Expedition as regards this 

 genus. 



In 1888, Dr. Ortmann f described the difference between Goniopora and Rhodarcea to be 

 that, while in Rhodarcea in the " younger, deeper, central " calicles, the pali are distinct, in 

 the "older (lateral)" calicles septa and pali fuse into a homogeneous spongy mass; in 

 Goniopora the reverse is the case, the pali are distinct in the " older " (lateral) calicles and 

 obliterated in the " younger " (central) calicles. 



In 1890, Mr. Bassett-Smith J noted two forms which he had discovered in the China 

 Seas. They are here described on pp. 72 and 73. 



In 1895, two fossils were attributed to the genus by Dr. Angelis § and named Rh. ambigua 

 and Rh. dissita, see pp. 121 and 113. 



The proposal to merge this genus with Goniopora was first made by the present writer in 

 1899 || ; the usual distinction having been found to be a matter merely of degree, and hence of 

 insufficient morphological importance (see further next paragraph). 



(d) Tiohopora. 



This genus was proposed by Mr. Quelch IT for a single small specimen from Samboanga. 

 It was said to differ from Goniopora in that its walls were only slightly developed, and did 

 not rise as strong distinct trabeculate laminae ; and, further, in having paliform spinules 

 more distinct in the central than in the lateral calicles. From Rhodarcea it differed in the 

 comparative indistinctness of the paliform spinules. As these differences are mere questions 

 of degree as soon as a large collection is examined, this genus was also merged in the extended 

 genus Goniopora by the present writer in the paper above quoted. || It will further be shown 

 lower down (see section on the morphology of the skeleton) that all massive Gonioporas 

 are Rhodarseas at the sides ! 



* On the various attempts which have been made to specify this coral, see the introductory 

 remarks to the Red Sea forms (p. 99). 



f ZooL Jahrb. (Syst.) iii. p. 158. J Ann. and Mag. Nat. Hist. (6°) vi. p. 457. 



§ Atti R. Accad. Lincei (5°) L p. 164. || Journ. Linn. Soc, xxvii. p. 144. 



IT Challenger' Report, xvi. 1886. 



