PTEROPODA 
OF THE 
NIAGARA, LOWER AND UPPER IlELDERBERG, HAMILTON AND WAVERLY GROUPS. 
TPINTACULITES, Schlotheim. 1826. 
(See Vol. V, part ii, pp. 155-165.) 
The following species of this genus are illustrated upon the supplementary 
plate cxiv: 
Tentaculites minutus. 
PLATE CXIV, FIGS. I, 2. 
Tentaculites mimitus. Hall. Pal. N. Y., vol. 2, p. 183, plate a 41, fig. 8a-e. 1852. 
Clinton group. Rochester, Monroe county. 
Tentaculites Niagakensis (Hall), var. Cumberlandia:, n. var. 
PLATE CXIV, FIGS. 3-6. 
This variety differs from T. Niagarensis, Hall (Pal. N. Y., vol. ii, p. 352, pi. 
Ixxxv, figs. 11, 12), in its more conspicuous interstitial annulations and more 
attenuate form. 
Niagara group. Cumberland, Maryland, 
Tentaculites gyracanthus. 
PLATE CXIV, FIGS. 7-13. 
Echinus gyracanthus, Eaton. Geological Text-book. 1832. 
Tentaculites irregularis. Hall. Pal. N. Y., vol. 3, p. 137, pi. vi, figs. 22, 23. 1859. 
Tentaculites gyracanthus, Eaton (Hall). Pal. N. Y., vol. 3. Expl. pi. vi. 
The Tentaculites regularis and T. irregularis of Castelnau (Essai sur le Syst. 
Sil. de I’Amer. Septentrionale, 1843), described as from the Trenton limestone, 
are probably from the Lower Helderberg group, and identical with this species. 
(See Pal. N. Y., vol. v, pt. ii, p. 156, foot-note.) 
