ON THE GENUS ALYEOLITES ETC. 361 



time perhaps improbable that future investigations will justify its 

 permanent retention. Rudimentary septa are by no means un- 

 known in Favosites, though not so regularly disposed or so striking 

 by their isolation as in A. suborhicularis ; and genera founded 

 upon single characters may be at any moment overthrown by the 

 discovery of intermediate forms. 



Group B. C(ENiTES, Eichwald. 

 With regard to the genus Goenites, Eichw., we wish merely to 

 suggest the possibility that it may ultimately have to be suppressed 

 if the genus Alveolites be retained for A. suhorhicularis and its 

 immediate allies. The genus was originally founded by Eichwald 

 in 1829 (Zool. Spec. i. p. 197), and was defined by him in the 

 ' Lethsea Eossica ' (vol. i. p. 457) as comprising dendroid or lamel- 

 lar and incrusting corals, with semicircular or triangular calices, 

 provided with a single rudimentary septal ridge on their lower lips, 

 the corallites being united by an abundant coenenchyma. In all 

 the above-mentioned characters, except the alleged presence of a 

 coenenchyma, the genus cannot be separated from ^ZweoZf^es as re- 

 presented by A. suborlicularis. The presence of a coenenchyma 

 would doubtless be sufficient ground for generic distinction ; but 

 the few observations we have been able to make on this point lead 

 us to doubt if a true coenenchyma exists at all in Goenites. More 

 especially, we have examined specimens of G. orientalis, Eichwald 

 (supplied to us from the Upper Silurian of Grotland through the 

 kindness of Dr. Lindstrom), by means of thin sections prepared for 

 the microscope ; and in this form we find the apparent coenenchyma 

 to be due to a secondary thickening of the walls of the corallites, 

 more particularly in the neighbourhood of their mouths, the ex- 

 ternal boundaries of the tubes remaining quite distinct. 



Group C. Pachtpoea, Lindstrom. 



In 1873 Lindstrom (" Nagra Anteckningar om Anthozoa Tabu- 

 lata^'' Ofversigt af. K. Vetensk.-Akad. Eorhandl.) gave the name of 

 Fachypora to a new genus of corals, to w^hich he assigned the fol- 

 lowing characters : — " Calices annular, at the extremities of the 

 branches obliquely semilunar, with sparse spiniform septa. The 

 calices surrounded by dense, delicate, concentric laminse, so as to 

 be superficially remote. Walls perforated with canals." The only 

 species described is P. lamellieornis, which is stated to possess 

 flattened branches, often coalescent and forming broad laminae, the 

 tabulse being extremely few or inconspicuous. 



Dr. Lindstrom has kindly furnished us with specimens of P. 



