64 
ANNALS NEW YORK ACADEMY OF SCIENCES 
[Zaphrentis] racinensis Whitfield. 
1882 Zaphrentis racinensis Whitfield, Geology of Wisconsin, vol. IV, p. 277, p^. 
XIV, figs. 1 and 2. 
Whitefield describes this species in the following words: 
Corallum forming a short, rapidly expanding, cup-shaped or turbinate body, 
nearly as wide as high, and strongly curved; calyx occupying nearly the entire depth 
of the body; the floor, in a specimen measuring one and one-quarter inches in 
diameter, not exceeding three-eighths of an inch in width; longitudinal or vertical 
lamellae moderately well developed, but very thin and distinctly alternating in size, 
increasing in number only along the primaries dividing the dorsal and lateral sections; 
those of the two sections on the inner side of the curvature are more numerous than 
the others, counting ten in each division, while those of the outer divisions are only 
eight on each side, making, to the entire cup, thirty-six primary lamellae on the speci¬ 
men figured; fosset deep, situated on the outer side of the curvature, very narrow 
and having only one primary lamella depressed within the cavity. 
The examples of the species observed are all internal casts of the cup, but are 
well marked and quite numerous. They present evidence of the outer surface hav¬ 
ing been transversely wrinkled, which, owing to the thinness of the-substance, have 
shown in the cup and been preserved on the cast of the interior. 
This species is found in the Niagara beds at Racine, Wis., and although 
represented only by internal moulds it is evidently derived from the Strep- 
telasma stem and has reached about the same stage of development as Entero- 
lasma caliculum, although in a different direction and along an independent 
line. 
In all probability, this is not a true Zaphrentis but belongs to a different 
genetic series, which in the Devonic gives rise to the genus Heterophrentis 
of Billings and in the upper Siluric beds gives rise to the genus Heliophrentis 
of Grabau which leads up to the terminal form Heliophrentis corniculum 
by a development parallel with that of the Heliophyllum line in the Devonic. 
As in Heliophyllum, this Heliophrentis line of development is characterized 
by the gradual addition of carinse on the sides of the septa. 
III. Devonic Corals. 
Throughout the deposits of the Lower and Middle Devonic the rugose 
corais are widely and abundantly distributed. In the lower beds are found 
forms very closely related to those of the Upper Siluric. In the middle beds 
the forms become more diversified, and in the upper beds they plainly show 
that they have passed the acme of development and are on the decline. 
