] 7 2 PA LJEONTOL 001' OF NE W TOR A . 



Tentacumtes spiculus. 



PLATE XXXI, FI08. -2I-2S. 

 Trntaculitrs xpirulits, Ham.. Illustrations of Devonian Fossils: Ptcropoila, pi. 36, fitrs. 81-85. HW6. 



PORM a slender-elongate, cumulated cone; very gently expanding from the 

 apex, and sometimes showing a tendency to cylindricity towards the 

 aperture: annulations ahruptly elevated, sometimes rounded and oblique 

 to the axis of the cone ; about equal to the spaces between them, and 

 gradually increasing in distance towards the aperture : ten to fourteen 

 annulations in the space of five mm. in specimens of the same size ; 

 apical portion very finely annulated or transversely striate, about twenty 

 in the length of one mm., while an equal distance measured near the 

 aperture gives eleven annulations. Interannular spaces on the body of 

 the shell marked by fine transverse striae, to be seen only under favorable 

 conditions of the fossil. Length of longest specimens from eight to ten 

 millimetres : ordinary length, four to six mm. 



This species is known almost entirely as imprints in argillaceous sand- 

 stone, and its characters are obtained from these and from gutta-percha casts 

 of the same. The extreme apical portion, in the condition in which the 

 fossil usually occurs, seldom preserves evidence of annulations. 



This species resembles the T. attenuatus in many of its characters, but the 

 annulations are thicker and more obtuse on the periphery, and the intermediate 

 rtriflB are fewer and stronger, as shown in a single specimen preserving the 

 shell towards the outer extremity, and as apparent in the impressions of the 

 exterior. This character, together with the common appearance of an obliquity 

 of the annulations, are all the features that can be indicated as distinguishing 

 the species from T. attenuatus, when in the ordinary condition in which the 

 two forms occur. 



Formation and localities. In some semi-arenaceous layers of the Chemung 

 group, a few miles south of Ithaca, N. Y., and in similar beds to the south of 

 Cortland village in Cortland county, N. Y. 



