70 PALEONTOLOGY OF NEW-YORt 



106. 4. STREPTOPLASMA CRASSA (n. yp.)- 

 Pl XXV. Figs. 3 a, b, e. 



Obliquely turbinate, slightly curved, gradually expanding upwards from an obtuse point ; 

 lamella; about fifty, coarse and strong ; surface marked by longitudinal lines coincident 

 witli tlie lamellae ; transverse lines obsolete. 



The whole aspect of this specimen is strong and coarse, differing essentially from the 

 last, which presents a neat symmetrical outline and surface. The interior presents some 

 apparent irregularity in the lamellae, showing a depression toward the more expanded side 

 of the coral, somewhat like Caninia. The structure otherwise, however, is unlike Caninia, 

 and, as in Streptoplasma, consists of simple vertical lamellae. 



This species resembles in some degree the one so common in the Black-river and Birdseye 

 limestones, but the lamellae are coarser and stronger, and equal in thickness to twice the 

 space between them. 



Fig. 2 a. Lateral view of a specimen, the edges somewhat broken. 



Fig. 2 b. Longitudinal section, showing the internal arrangement of the lamellae. 



Fig. 2 e. View of the cup, showing imperfectly the meeting of the lamellce in the centre. 



Position and locality. Trenton limestone, near Middleville. Rare. 



107. 5. STREPTOPLASMA MULTILAMELLOSA (n. jp.). 



Pl. XXV. Figs. 3 a, b, e. 



Obliquely turbinate, somewhat curved, rapidly enlarging above ; cup moderately deep ; 

 lamellae about 120, thin, edges apparently slightly crenulated ; exterior covering thickened, 

 smooth. 



This species somewhat resembles the iS. comiculum in form ; but it is more robust, the 

 lamellae more numerous, and the cup more shallow. The outer edges of the lamellae, 

 where denuded of their covering, appear to be crenulated or wrinkled, and the spaces 

 between them are twice their thickness : this last character alone is probably suflScient to 

 distinguish the species from the two preceding. 



Fig. 3 a. Lateral view of a specimen, somewhat shortened from wearing off of the smaller extremity. 

 Fig. 3 b. Transverse section, showing the thin lamellse. 

 Fig. 3 e. An enlarged portion of the denuded outer surface. 



Position and locality. In the grey crysta:lline part of the Trenton limestonje, Watertown, 

 Jefferson county ; and near Trenton, Oneida county. (State Collection.) 



