PLATE XV A.— Continued. 



Fiir 15 The inteiioi- of a brachial valve. The cardinal process consists of two independent apophyses, 

 not coalesced with the crural plates, the latter beinff depressed at their orifcin bvit con.siderably 

 elevated at their extieniities. The visceral rejnon is concave on either side of a broad median 

 i-idge and its surface radially striated ; from its anterior margin the surface of the valve is 

 abruptly and evenl)- deflected. X 5. 

 Fig. 16. Cardinal view of the same specimen ; showing the wiilth of the area, the posterior face of the car- 

 dinal process and the elevation of the crural jilates. X S. 

 These figures ai-e from the original specimens of the species. 



••Point Levis; in the upper part of the Limestow. No. 2, Quebec group." (Billing.s.) 



Genus ANOPLIA, gen. nov. 



(See Plate XX.) 

 Page 309. 



Anoplia nucleata, Hall. 



Fig. 17. Cardinal view of an internal cast of the pedicle-valve, retaining the impressions of the extremely 



oliliijue dental lamella? and the short median septum ; also showing the indistinct outline of the 

 njuscular area. X ii. 

 Fig. IS. The interior of the brachial valve which has a close similarity to that of Chosetes. X 2. 

 Oriskany sandstone. Albany county, N. Y. 

 See also the illustrations in Palfeontology of New York, Volume III, plate 91, tigs. 1 a-d. 



Genus LEPT^NISCA, Beechee. 



Page 300. 



Lept^nisca concava, Hull. 



(See Plate XV, figs. 30. 31.) 

 Fig. 19. The exterior of a pedicle-valve ; showing the contour and character of the surface. X 2. 

 Fig. 20. The interior of a brachial valve, somewhat imperfect about the margins and cardinal process, 



but .showing the spii-al brachial i-idges and the thin median septum. X 2. 

 Fig. 21. Cardinal view of an imperfect lu-achial valve preseiving the character of the cardinal process, 

 which is deeply quailriloliate, X 3. 

 Figures 20 and 21 are from specimens illustrated by Mr. Beecher. 

 Lower Helderberg group. Near Clarksville, N. Y. 



Leptjenisca adnascens, sp. IIOV. 



Fig. 22. A pedicle-valve attached by nearly its entire outer surface to the interior of a valve of Orihis 

 oblata. The specimen shows the dental lamellse and median ridge dividing the muscular ai-ea. 

 X 3. 



Fig. 23. A specimen retaining both valves, attached to Or(AljpereZeja7i.s. X 4. 

 Lower Helderberg group. Near Clarksville, N. Y. 



Lept.«:nisca tangens, sp. luiv. 



Fig. 24. The exteiior of a pedicle-valve with the umbo flattened from attachment, and showing the low 



median sinus. X 2. 

 Fig. 2.5. The interior of the same specimen ; showing the c.icatrix of attachment (x), the deltiiliuni and the 



dental lamella' X 2. 

 Fig. 26. The exterior of a pedicle-valve in which the rugose growth has obscured the median sinus. The 



deep undional depression has been caused by attachment to some bryozoan. X 3. 

 Figs. 27, 28. Opposite sides of a pedicle-valve attached to a twig of 'i'REMATopoRA. X 3. 

 Figs. 29, 30. Opposite sides of a similar valve which has been attached to a frond of Fenestella. X 3. 



The.se last two specimens show the t)ilol)at<' exterior, the deltidiinn, teeth, strong dental lamellse 

 produced al>out the muscular area, and the short median septum. 

 Lowei- Heldeilierg group. Niar Clarksville, N. Y, 



