GONIOPORA. 15 



distinction drawn by Dana between Goniopora and Porites, viz. that the former were larger 

 with twenty-four septa while the latter had only twelve, has not been found satisfactory. 

 Fossil perforates are found with all numbers from twenty-four and more, to twelve and fewer 

 and yet having all the distinguishing characters of true Poritids. This distinction is never- 

 theless useful and is often followed here. An important morphological distinction recently 

 discovered by the present writer and described below, p. 20, is not always available, 

 and then recourse must be had to the older distinction, based simply upon the number of 

 the septa. 



Over 40 fossil forms of Goniopora had thus been described under various names. Reuss 

 alone described and figured 14, while others occur in the works of Michelotti, Catullo, 

 d'Achiardi, Martin Duncan, Martin, Sismonda, Posta and Angelis (see Table II. p. 168). 



The histories of two other genera, merged with Goniopora by the present writer, viz. 

 Bhodarcea M.-E. & H., and Tichopora Quelch, have still to be given. 



(<;) Rhodarsea. 



This genus was founded by Milne-Edwards and Haime in 1849 * for the Astrcea calycularis 

 of Lamarck, which became " Bhodarcea calycularis " M.-E. & H. It found its place among 

 the Poritidse next to Goniopora. This latter genus was described as having walls distinct, 

 elevated and fenestrated, with well- developed fenestrated septa, spongy columella, without 

 pali (see p. 152) ; whereas Bhodarcea was said to have thick walls which are only slightly 

 elevated, with rudimentary septa, and pali very well developed and forming a rosette in the 

 middle of the calicle. 



According to this description, and apparently on account of the lower wall and well- 

 developed pali, Bhodarcea was placed between Porites and Goniopora. This order was 

 maintained in the ' Monograph of the Poritidse.' f In 1860, in vol. iii. of ' Les Coralliaires,' 

 by Milne-Edwards alone, two fossil genera Protarcea (Silurian) and Litliaraza (Eocene) 

 intervene between Bhodarcea and Goniopora, which last was said to lead on to Alvcopora.% If 

 the series was mainly based upon the height and character of the walls we should logically 

 be compelled to complete it by placing the genus Synarcea of Verrill in the first place 

 because these are Poritid forms in which all traces of raised walls are obliterated. The order 

 is mainly interesting because it shows that the genus Goniopora was supposed invariably to 

 have tall thin walls. 



In the monograph above quoted,§ the authors added two more " species " : Bh. lagreneii 

 (doubtful) and Bh. raidini (foss. Miocene) and in 1860, || a fourth Bh. gracilis. 



The next mention of the genus was in 1878 by Briiggemann. If This author described a 



* C.R., xxix. p. 259. f Ann - Sci - Nat - ( 3 °) jyi - 1851 - 



| On this, see p. 2 of this volume. Ann. Sci. Nat. ( 3°) xvi. p. 43. 



|| 'Les Coralliaires,' p. 184. f Abh. Ver. Brem., v. p. 547. 



