42 
to Micro-Palcontology. 121 
surface, the corallites become separated by the development 
of the interstitial tubes, which entirely resemble the proper 
corallites in structure, except in the fact that they possess a 
much larger number of tabule, these structures, however, 
being still horizontal and complete, and not assuming a vesi- 
cular character. 
As regards the generic position of this species, I find it 
necessary to make a few remarks, as I have elsewhere (Pal. 
Tab. Cor. p. 304) expressed the opinion that Callopora, 
Hall, should be regarded as a synonym of Pistulipora, M‘Coy. 
I arrived at this view from a study of the description and 
figures given by Prof. Hall of Callopora, from an examination 
of M‘Coy’s type species of F’studipora, and from an investi- 
gation of various corals which appeared to be precisely similar 
to various forms included by Prof. Hall under Callopora. 
That Callopora, Hall, has been made by its original 
founder, as well as by other paleontologists, to include a 
large number of heterogeneous forms, and that some of these 
are truly referable to /istulipora, M‘Coy, are points which 
appear to me to be free from doubt, and it was therefore not 
unnatural ‘that I should ave concluded that the two genera 
were identical. 
Recently, however, this question has been attacked in a 
more satisfactory manner by Mr. Ulrich (Journ. Cincinn. 
Soc. Nat. Hist. 1882), who has had the opportunity of 
examining by means of thin sections authentic specimens of 
Callopora elegantula, Hall, which is the type species of the 
genus Callopora, Hall. Mr. Ulrich has shown that this 
species differs in its structure from the majority of the nume- 
rous forms referred by Prof. Hall to Callopora, and that it 
exhibits characters entirely similar to those of various Monti- 
culiporoids which I included under the name of Heterotrypa, 
and certainly quite unlike those of Sistulipora, M‘Coy. 
While 1 am not prepared to admit the justice of all the re- 
marks which Mr. Ulrich has seen fit to make upon this 
subject, I am quite ready to recognize the new light which 
he has thus thrown upon the structure and affinities of Callo- 
pora, Hall. I also quite recognize that Heterotrypa, as origi- 
nally defined by me, is a wide group which may be ad- 
vantageously subdivided. For these reasons, therefore, I 
shall accept the genus Callopora, Hall, as defined by Mr. 
Ulrich, as including Monticuliporoids of the type of the 
present species, with numerous interstitial tubes, which re- 
semble the normal corallites in all except their size and their 
possession of more numerous tabule. The corallites, more- 
over, are always rounded, and their walls are amalgamated. 
Ann. & Mag. N. Hist. Ser. 5. Vol. xiii. 9 
