PLATE I. 



Legend, g. Uniljoiuil scars. c. Conci-ete centrals. 



1. Lateral scars. i. Transmedian scars, 



'k. Middle latei-als. d. Cardinal area, 



j. Anterior laterals. s. Median septum.^ 



1. Outside laterals. s'. Latei-al septa. 



X. Concrete laterals. • vs. Vasculai- ti'unks. 



h. Centi-al scai'S. v. Vasculai- bi-anches. 



LINGULA, Bbugui^ire. 



Page 2.1 



Glossina, Phillips. 



Page 15. 



LiNGULA (Glossina) acuminata, Conrad. 



Fig-. 1. A pedicle-valve from -which most of the substance of the shell has been exfoliated, presenting a 

 cast of the internal surface, which i-etains the impressions of the fine i-adiating, and coai-ser, 

 more distinct, concentric lines. The thicknes.s of the shell-sulistance and the undulating char- 

 acter of its laminse, is shown on the marginal portion of the tigui-e, but no ti-aces of muscular 

 impressions are discernible. X 2. 



Kig. 2. A bi-;\chial valve of the sanie siiecies, from which the shell is partially exfoliated. X 2. 

 Calciferous sandstone. Saratoga, iV. T. 



LiNGULA (Glossina) riciniformis, Hall. 



Fig. 3. A pedicle-valve (?) from -which the outer layers of the shell are somewhat exfoliated ; showing the 

 strong median i-adii, which are evidently more distinctly developed on the intei-ior than on 

 the extei-ioi- of the shell. X 3. 



Trenton limestone. Middleville, N. Y. 



LiNGULA Vanhoknii, Miller. 



Fig. 4. The interioi- of a pedicle-valve ; showing the undifferentiated lateral muscular scars, and the low, 

 median septum. X 3. 



Hudson River group. Cincinnati, Ohio. 



LiNGULA Procteri. Ulrich. 



Fig. 5. The brachial valve of an internal cast : showing the concrete laterals (x), the anterior laterals (j), 



and the septum (s). X 1-.5. 

 Fig. 6. The opposite valve of the same specimen ; showing the progi-essive lateral and median impres- 

 sions (sejltum) and the vascular markings. X 1-5. 



Hudson River group. South Covington, Kentucky. 

 Fig. 7. An internal cast of a brachial valve ; showing the lateral scars and long median septum. X 2. 

 Hudson River fgroup. Cincinnati, Oliio. 



LiNGULA Philomela, Billings. 



Fig. S. A pedicle-\'alve (?), imperfect in the umbonal region ; illustrating one extreme of outline attained 

 by shells of this genus. Natural size. 



Trenton limestone. Florenceville, Hntoard county, Imoa. 



LiNGULA LAMELLATA, Hall. 



Figs. 9, 10. External and internal views of the same specimen. Natural size. 

 Niagara group. Lockport, N. Y. 



LiNGULA GUNEATA, CoUl'acl. 



Fig. 11. An internal cast of the pedicle-valve ;. showing the broad, lo-n^ median septum and the faint lateral 



scars. X 2. 

 Fig. 12. The brachial valve, with an ill-defined muscular scar and traces of the vascular sinuses. 

 Medina sandstone. Albion, N. Y. 



