of the Anthuzoa Tabulata. 5 



tlieir predecessors, one beneath the other, like so many in- 

 verted funnels. It was recently pointed out to me by G. Eisen 

 that there are large specimens found in Gotland combining 

 the peculiar features of Labechia with those of Cosnostroma; so, 

 perhaps, there may also be reason to eliminate the latter from 

 the Anthozoa. 



Next we have to consider a great variety of other fossils 

 which are generally stated to be Tabulata, but Avhich in reality 

 are Bryozoa. Foremost stands the genus Monticuh'pora. If 

 numerous specimens of the common Silurian M. pef.ropolitanay 

 Pand., be closely scrutinized, it will be seen that its semi- 

 globose colony, so closely resembling a Favosites in its initial 

 development, has an origin that could hardly be suspected. 

 It begins, indeed, as a Bryozoon, as a Discoporellaj as what 

 Hall has termed Ceramopora imhricata (Pal. N. Y. vol. ii. 

 p. 169, pi. 40 E. figs. 1 rt-1 i). Tliere can be no doubt that 

 this is closely allied to the recent Discojwrella (see Fr. Sraitt, 

 CEfvers.Vet. Akad. Forhand. 1866, p. 476, pi. xi. fig. 4). The 

 basal surface of a MonticuUpora^ when the epitheca is very 

 thin, clearly shows that it is in its first origin a Ceramopora. 

 The smallest Cerarnoporce which I have hitherto seen consist 

 of a thin circular disk with elevated edges. From the smooth 

 centre of the superior surface four or five wedge-shaped zooecia 

 radiate outwards, each of a length of i millim., their mouths 

 being oblique, with the inferior lip somewhat protracted. On 

 both sides of the mouth there is a short, pointed spine. In its 

 interior such a zooecium is transversely divided by some irre- 

 gular tabulas. The interstitial ribs, which are so characteristic 

 of the Discoporellida3, are also distinctly seen between the 

 zooecia of Ceramopora. New zooecia are budded forth in quin- 

 cunx from the corners of the old zooecia ; and in the periphery 

 of the colony they become more crowded, having the mouth 

 oval and erected. In the interstices is seen what might be 

 taken to be a coenenchyma ; but this in reality is composed of 

 nothing but smaller iri'egular zooecia. When the colony has 

 spread out laterally, tliere are seen at the sides of the first 

 smooth centrum several others regularly distributed on the 

 surface, from which zooecia radiate, just as if the disk were 

 composed of an aggregation of coalescent initial buds. When 

 the colony has thus gained the expanse of an inch or more, 

 the zooecia grow vertically upwards ; and the colony by-and- 

 by assumes a semiglobular shape, and is converted into a 

 Monticulipora. All the zooecia are then tubular, tlieir mouths 

 quite circular, and armed with a pair of very short spines, their 

 size varying in difterent cases. The larger zooecia have around 

 them either an empty space or^ as above stated, a cellular 



