umie.] CANADIAN PALAEOZOIC CORALS. 55 



stunted groups, in which the corallites are much bent and confused. The 

 connecting processes are very short and distinct, and appear to be some- 

 times mere inosculations of the stems. The corallites after growing sepa- 

 rately for a short distance, approach each other and seem to grow together 

 or adhere to each other for the space of a line and a half or more, they 

 then diverge and again unite. These points of contact occur at distances 

 varying from three lines to six, nine, or even twelve lines. Externally 

 they exhibit numerous other indistinct annulations, and also faint indi- 

 cations of longitudinal striae." (Billings.) 



In 1860 Mr. Billings, who had previously identified this species with 

 S. tubiporoides, Yandell and Shumard, found that it was really quite 

 distinct and proposed the specific name Maclurei for the Canadian coral. 

 He also qualified the original description by stating that the average 

 diameter of the corallites is more nearly one line than one line and a 

 half (vide Can. Jour., vol. V). 



The exterior of the corallites of this species presents a rather smooth 

 surface, the annulations or lines of growth being faint and indistinct, but 

 indications of longitudinal strife have not been observed by the writer. 

 The diameter of the corallites varies in different specimens from 

 1J to 1 line, and there is a certain amount of variation in individual 

 specimens ; the average thickness appears to be slightly over 1 line or 

 about 2*5 mm In specimens with very flexuous corallites the growth 

 seems to be more robust than when the corallites are comparatively 

 straighter and closer together. Connecting tubes proper, though seldom 

 seen, are short and stout, most frequently the corallites touch each other 

 and are brought into communication with each other without the inter- 

 vention of tubes. 



The writer has examined the type specimens of Aulopora cornuta, 

 Billings, in the museum with a view to the elucidation of, if possible, some 

 of its characters. The fossils are fragments only and have been damaged 

 by the action of acid so that many details of structure are lost. On a 

 close examination, however, the broken ends of some of the tubes show 

 what appear to be the remains of " infundibuliform tabulae," seen in cross 

 section, wth evidences of a central tube. Also, a longitudinal section 

 obtained by rubbing do.vn one of the branches, revealed the usual syringo- 

 pora-like structure, from which the writer is led to believe that this 

 fossil should properly be referred to the genus Syringopora. Further, a 

 comparison of the types of Aulopora cornuta with examples of Syringo- 

 pora Maclurei, Billings, suggests the probability that the former species 

 was founded on portions of the basal growth of the latter species. 



Dr. Rominger (op. cit, p. 71) regards A. cornuta as a synonym of 

 Romingeria umbellifera,h\it seems to be guided entirely by external char- 



