378 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvm. 



^'Family MICKOSOLENID.E, Koby, em. 



"Simple or colouial Fuiigida in which the septa are palissades of 

 more or less vertical, disconnected, regular or irregular trabiculifi. 



"Cieiiera: Anahacia, Euwakds ami Haime. 

 "Genera: Gruabuda, Edwards and Haime. 

 "Genera: Trocharnca, Etallon. 

 "Genera: Trochojdegma, Gregory. 

 "Genera: Microsolcna, Lamouroux. 

 "Genera: Tr icy closer is, Thomes. 

 "Genera: Dimorpharaea, de Fromentil. 

 "Genera: Thamnaraea, Etallon." 



BASIS OF THE CLASSIFICATION HERE PROPOSED. 



Following the lines of the investigations of Pratz, Gregory, and 

 others, the larger divisions are based upon septal structure; that is, 

 whether the septa are solid or perforate; if perforate, whether they are 

 more pronouncedly laminar or tral)ecular in composition, and I have 

 also utilized in defining the families the character of the wall, whether 

 normally perforate, even if only slightly, or whether normall}^ solid. 

 The genera are separated by columellar characters, the relative com- 

 pactness of the septa, the presence or absence of paliform processes, 

 costal characters (whether corresponding or alternating with the 

 septa), and the e[)itheca. The value of the epitheca in separating 

 genera has })een severely attacked," Gregory says, "There is no part 

 of a coral skeleton over which more time has been wasted than over 

 the epitheca.'"' From a study of large numbers of species belonging 

 to the same genus, I am inclined to believe that the so-called complete 

 epitheca is, in some instances at least, a generic character. There are 

 genera in which epitheca is normally a])sent, and others in which it 

 ma}^ exist in an imperfectly developed condition. Epitheca can not 

 be considered to possess the importance once attached to it, but I 

 believe that its su})posed value as a classifactory character has not been 

 entirely disproved. 



TENTATIVE CHARACTER OF THIS CLASSIFICATION. 



I have distributed the genera, considered in this paper, among four 

 families, and have five headings for genera that are not referred to 

 families. This classification, which embodies nothing new, except 

 n)aking a family, MlcrahacUd^, is only an attempt, and should be sub- 

 jected to the most searching criticism to determine the validit}' of the 

 characters used in differentiating the families. The Leptophylliidse^ 



"Gregory, Jurassic Fauna of Cutcli — the Corals, p. 11. 



''The same as Gregory's Ethmoiklx, which is abandoned, as it was not derived from 

 a genus name. 



