148 



MOLLUSCA. 



articulated genera, those having spiral arms appeared first • those with 

 calcareous spires disappeared with the Lias period. Of the 77 Lower 

 Silurian New York species, 51 are restricted to the Trenton Limestone. 

 Brachiopods furnish the most numerous instances of recurrence, owing 

 to their tenacity of life. 



No. 690. Spirifer pinguis, Sow. 



This Brachiopod, and the fifteen following, 

 belong to the Spiriferidce., a family characterized 

 by the possession of internal calcareous spires 

 (the mineralization of their coiled arms) 

 extending from the centre of the shell outwards. 

 From the Carboniferous limestone of Kildare, 

 near Dublin, Ireland, and now in the Ward 

 Museum of the University of Rochester. 



Price, $0.30. 



No. 691. Spirifer arenosus, Conrad. 



From the Oriskany sandstone (Devonian), New York, and now in the pri- 

 vate Geological Cabinet of Mr. Ward, Rochester. Cast of the interior. 



Price, $0.80. 

 No. 692. Spirifer cameratus, Morton. 



From the Coal Measures, Wintersett, Iowa. Price, $0.25. 



No. 693. Spirifer G-rimesi, Hail. 



From the Burlington limestone (Sub-carboniferous), Burlington, Iowa. 



Price, $0.50. 



No. 694. Spirifer Logani Hall. 



From the Keokuk limestone (Sub-carboniferous), Nauvoo, 111. Price, $0.50. 



No. 695. Spirifer macro pleura, Conrad. 



From the Lower Helderberg (Upper Silurian), Albany Co , N, Y. 



Price, $0.25. 

 Price, $0.25. 



No. 696. Spirifer Oxypteris, Burvignier. 

 From the Lias of Carignan, France. 



No. 697. Spirifer pennatus, Owen. 



Shows well the area and deltidium. From the Hamilton group (Devonian), 

 Independence, Iowa. Price, $0.30. 



No. 698. Spirifer striatus, Martin. 



This specimen of S. striata (the type of the genus) was found in the Car- 

 boniferous limestone at Enniskillen, Ireland. Price, $0.90. 



No. 699. Spirifer Verneiiili, Murch. 



Long variety. From the Chemung group (Devonian), Southern New York 



Price, $0.50. 



No. 700. Spirifer Verneuili, Murch. 



Group on slab. From the same locality as the preceding, and now in the 

 private Geological Cabinet of Mr. Ward, Rochester. Size, 9x6. Price, $1.00- 



