30 PERMIAN FOSSILS. 



Not being sufficiently acquainted with the typical species of this genus {Alveolites: 

 escJtaroides, from the environs of Dusseldorf, — query, Carboniferous or Devonian), I am 

 not prepared to say how far it agrees with or differs from the apparently allied genus 

 Calamopora. Reverting to Alveolites, probably the principal differences between it and 

 the last consist in the shortness of the cells, their want of internal transverse plates, 

 and their terminal mode of reproduction. These characters, keeping out of view the 

 want of transverse plates, also appear to constitute the difference between the present 

 genus and Stenopora. 



Most of the Alveolites are yet only known in a fossil state. (Lamarck.) 



Alveolites Buchiana, King. Plate III, figs. 10, 11, and 12. 



Diagnosis. — Tubes or cells adjoining, cylindrical, leaning, concavely arcuate 

 ascendingly, alternately overlying each other, and slightly wrinkled more or less 

 transversely. Apertures regularly arranged, circular, occasionally polygonal, margined 

 by a circle of from twelve to fourteen small, closely-packed tubercles, which generally 

 fill up the interspaces. 



This pretty Coral, which is dedicated to one of our most profound palaeontologists, 

 differs from Stenopora columnaris in the more regular arrangement of its apertures, 

 in the general absence of interpolated tubes, and in being composed of a single 

 tubular layer. The interspaces are generally wide enough to admit of the presence 

 of the tubercles belonging to two adjoining apertures (vide PI. Ill, fig. 11): when 

 wider, an interspace is here and there perceived, containing a small opening, which 

 may belong either to additional interpolated tubes, or to old ones which have become 

 decrepit. The apertures are regularly arranged, more so than those of Stenopora 

 columnaris, and decidedly more uniform in their arrangement than the corresponding 

 structures in Calamopora Mackrothii. The tubercles appear to be hollow, and con- 

 nected with foramina, which a high magnifying power discloses on the interspaces 

 when they (the tubercles) are abraded. 



The only reason why this Coral has been separated generically from the last, is its 

 mode of growth, a character which renders it doubtful whether Alveolites is the 

 genus to which it really belongs. It seems advisable, however, to retain it in its 

 present position, deferring all discussion on the matter until more is known of the 

 structure of those palaeozoic Corals Avhich Lamarck placed in his fourth and fifth 

 sections — " Polypiers a reseau ' and " Polypiers foramines." 



Alveolites BucJiiana is a scarce fossil, having only occurred to me once in the Shell- 

 limestone at Humbleton-hill Quarry. 



