866 MANUAL OF THE MOLLUSCA. ! 
Shell ornamented with rounded ribs; beak very long, divided 
lengthwise internally by the dental plates; loop doubly 
attached? Distribution, 4 species cretaceous. Europe. Three 
species of similar form are found in the Trias of St. Cassian. 
Magas (pumila), Sby. Fig. 153. 
. Shell smooth, conspicuously punc- 
\\t tate, dorsal yalye impressed, fora- 
men angular, deltidium rudimen- 
tary; internal septum (s) prominent, 
touching the ventral valve; reflected 
portions of the loop disunited ((). 
Fig. 158. I. Pumila.2 3 species. U. Green-sand—Chalk. 
Kurope. Distribution, 2 species. 
New Zealand; Canaries. The recent Ter. Cumingii, of New 
Zealand, resembles Bouchardia externally, but has the 
diverging processes of the loop as in Magas. 
0 
Fig. 154. B. Tulipa, Bl.* 
Bouchardia (tulipa), Davidson, Fig. 154. Beak prominent, 
with a minute apical foramen (/); deltidium blended with the 
Animai. +,° Fig. 155. Dorsal valve. 
shell (d); apophysis anchor-shaped, the septum (s) being fur- 
* The rouscular impressions in Bouchardia have been compared with those of Zer. 
Cumingii, of which the animal is known. The large impressions (r) in the disk of the 
ventral valve appear to be formed by the cardinal muscles; a, by the adductor; p, by 
the pedicle muscles. 
+ Fig. 155. c, loop; f, pedicle notch; 0, the ovaries. From the originals in Mr, 
Davidson's collection; magnified ten diameters. 
