Fig. 

 99. Rhynchonella loxia, Fischer, from Moscow, type of the genus Rhynchonella of Fischer. 



100. ,, ^.«7<acea, genus jGTemiMym of M. d'Orbigny ; d, deltidium. 



101. „ ,, \wtmov o? dorsal valve : «', foramen for the passage of the intestine, 



102. ,, ,, Interior of the ventral valve. 



10.3. „ octoplicata. A fragment of the interior, to show the position of the teeth, and 



dental plates, x. 



104 & 107- J. scaldinensis, D'Archiac, to show the tubular expansion of that portion of the 



deltidium which encircles the foramen. 



10.5. ., rimosa. To show that from the great incurvature of the beak, there exists no 



visible foramen in some species. 



106. „ concinna. Fragment of the beak, to show that the deltidium does not always 



surround the entire foramen, which is partly completed by the 

 umbo of the dorsal valve. 



108, 109. Camakophoria ScHLOTHERMi. Type of the gcuus. 



110. ,, ,, A specimen with lamellose marginal expansions, from the col- 



lection of Professor King. 



111. „ multiplicata. King. Internal cast. 



112. ,, „ Interior of a portion of both valves. In the dorsal valve is seen 



the disposition of tlie septum, s ; spatula shaped process, G ; 

 curved lamellae to which the oral arms were attached, c ; car- 

 dinal process, J. In the ventral valve, the septum, s, and con- 

 joined dental plates, x. 



1 13. ,, ,, Section of the same, to shew the projection of the different parts ; 



both these last figures are drawn from specimens kindly lent me 

 by Professor King. 



1 14. Pentamerus galeatus, Dal. The letter s, indicates the position of the septa in the dorsal and 



ventral valves. 



115. „ ,, Longitudinal section of the same. 



116. „ Knightii. Type of the genus. Longitudinal section, shewing the position and shape 



of the largely developed septa and plates. 



117. „ galeatus. Transverse section, to shew the relative position of the parts visible in 



the longitudinal section, fig. 115. 



llj^. „ liratus. A fragment of the dorsal valve, from a specimen in the Mus. of Prac. 



Geol., shewing, besides the adductor impressions, the processes, 

 c, to which the spiral arms were attached. 



119. ,, linguiferus. Exterior. 



120. PoRAMBONiTES ^auiROSTRis, Schl., sp. Viewed from the beaks; the letters b and x indicate 



the place and position of the plates. 



121. „ „ Profile of the same. 



122. ), >. Fragment exhibiting external sculpture (not punctation). 



123. 124. ,) intercedens, Pander. 



12"), 126. ,, Ribeiro, Sharpe. Internal cast, showing the position of the plates, and muscular 



and vascular system, from a specimen in the collection of Mr. Sharpe. 



127. Orthis calligramma. 



128, 129. ,, striatula or sinuata, showing the double area and fissures, = genus Schizophoria, King. 



130. „ ,, \niex\ov of ventral valve, hoTO.'^ehovi. 



131. ,, ,, Interior of dorsal or socket valve, from Nehou. 



132. ,, ,, Fragment of the same valve, from a specimen from Chi may. 



133. J, „ Internal cast of the t/oraa/ 2;a/«;e, drawn from a beautiful specimen presented 



by M. de Koninck to the British Museum, shewing the quadruple im- 

 pression of the adductor, ovarian spaces and vascular impressions. 



134. „ eleganiula, Dal. Interior of dorsal valve. 



135. „ resupinata. Interior of dorsal valve, from a specimen in the British Museum. 



