On Streptelasma Profundum. — Sardeson. 281 
The first good description of the species is that by Edwards 
and Haime. Their specimens were from the upper part of the 
Cincinnati stage (Hudson stage) of Ohio and therefore the 
largest of the species — tlie same as Billings called S. rusticmit. 
They are described as long conical, gently curved and partly 
attached by the apex. The beginning is a small point, from 
which the single cell or cup expands, curving gently, though 
most strongly during the first growth. The wall is marked 
by fine lines of growth. The septa are about 130 in number, 
sublamellar, alternatingly a little unequal, generally straight, 
and laterall}^ striated. One dorsal line and two lateral lines 
are marked by the obliquity of the neighboring septa to them 
and these coincide with the primary sej^ta. Tlie septal fosette 
is small and lies on the convex side. 
Billings (op. cit. p. 123) says that the "growth of these 
corals appears to have been as follows: At first they consist 
of a mere point attached to the rock, when the cup commenc- 
ed to form there were only four partitions or lamellne, as it 
increased others were added, three of the original ones contin- 
uing to grow and the fourth being undeveloped." The fourth 
one is developed however, though it is not marked otf by the 
obliquity of other lamella, which has been proved by Kunth, 
who has described extensive observations on the Tetracoralla. 
The development of the septa as described by Kunth will be 
considered in detail further on. 
A comparison of the geologically older with the younger 
representatives of tlie species — for example the specimens from 
the Beloit formation of Wisconsin with others from Richmond, 
Indiana — brings into contrast the average smaller size of the 
former specimens, but the difference is one which is indica- 
tive of a longevity of the latter as compared to the former, and 
not of any varietal difference. Both developed alike except 
that the latter grew longer and evidently lived longer. The 
corallum begins as a mere point, rapidly expands into ;i con- 
ical cup, increasing in diameter to a certain stage, after which 
it continues in length almost without increase or even with 
diminishing diameter. The rapidly expanding portion is, as 
Edwards and Haime said, the more curved, and it represents 
the period of increasing numbers of septa. Except in the later 
representatives, those of the Hudson i)erind, the litth^ curved, 
