Dr. Rominger on Pleurodyctium problematicum. 83 
he opposite side of the cavity, which forms the roof over 
the convergent smaller ends of the columns, is free, but closely 
The vermicular body, frequently noticed adhering to or pene- 
ae the root end of Pleurodyctium, is also seen in my speci- 
en, 
I was greatly surprised at observing the same vermicular per- 
foration in some small specimens of A/ichelinia, which also in all 
other respects appear to be specifically identical with the coral 
of which the European Pleurodyctium is a cap. 
The specimens were found in the shales of the Hamilton group, 
Cay wga county, New York, and are in the possession of Prof. 
Winchell of Ann Arbor. They form small cakes of not muc 
©ver one’ inch in diameter, The lower side is almost flat, cov- 
ered with a concentrically wrinkled epitheca; the upper side is 
Semi-globular, and shows the mouth-ends of conical subangular 
tubes, the larger ones of which measure from 4 to 5 millimetres. 
On the polished vertical sections of the coral, longitudinal 
tne and rows of spinules, together with numerous side-pores, 
are visible along the walls of the tu 
T 1€ Upper part of the tubes is generally filled with calcareous 
Matter, and shows no diaphragms, which are onl reserved in 
a lower ends, and are in part simple, straight; in part vesi- 
ar, 
li The vermicular channel traverses the substance of the coral. 
QM, irrespective of the direction of the tubes, and seems to cut 
Straight stecugh them. After some flexures it ascends to th 
