LONSDALE ON MIOCENE CORALS FROM N. AMERICA. 501 



a. Eeteropora tortilis. Natural size. General appearance of the coral, and 

 mode of branching. 



b. Portion of the same specimen greatly enlarged, exhibiting characters of the 

 surface, and showing the variable size and circular form of intersected tubes, as 

 well as the distinct walls, and the general appearance of the intermediate matter. 



c. Vertical section, greatly magnified, to show the mode of radiation, and of 

 interpolating additional tubes. 



three species of Prof. Goldfuss's CERioPORiE, has not been de- 

 scribed either by its founder or by other authorities with sufficient 

 fulness to enable an opinion to be formed of its complete charac- 

 ters, or of the nature of the minor openings, one of the assigned 

 essential structures ; nor does Goldfuss's account of the three 

 species afford satisfactory additional details of peculiarities of 

 composition. An examination of his figures (Petref. pi. 10. f. 3. 

 5. 9.), as well as those of the two species of Lamouroux's fossil 

 Milleporce (Exp. Methodiq. pi. 82. f. 7, 8. pi. 83. f. 6, 7.), removed 

 by M. Milne Edwards to Heteropora (Lamarck, 2nd edit. t. ii.) will, 

 it is conceived, justify the conclusion that the genus consists of 

 tubular corals ; and perhaps the inference that the smaller open- 

 ings are the terminations of interpolated immature tubes, in no 

 respect analogous to the fine pores in young branches of Myria- 

 pora truncata (De Blainville). Should these suppositions be 

 correct, the American fossils would agree with those figured by 

 Goldfuss and Lamouroux to the extent inferred : still there are 

 essential characters neither noticed nor represented by those au- 

 thorities or others in describing the same fossils, as the existence 

 or not of transverse diaphragms, the nature of the walls of the 

 tubuli, and whether the coral underwent any changes during 

 growth or subsequent to maturity ; and without a perfect acquaint- 

 ance with which, generic determinations in this division of poly- 

 parians must be always unsatisfactory. The impossibility of 

 comparing fully the American specimens with the structure of 

 those on which M. de Blainville established his genus Heteropora, 

 required, therefore, that the assignment should be given with 

 a doubt. 



