ORDER IV 



TELOTREMATA 



a large pedicle opening common to both valves. In the dorsal valve there 

 is a high vertical plate to which are attached the descending branches ; 

 ascending branches not represented. Recent. 



Ismenia, King. Coarsely plicate shells with the loop consisting of 

 fimbriate descending branches and simple ascending branches. Jura. 



MwUfeldtia, Bayle (Megerlea, King), (Figs. 558, 559). Jura to Recent. 



Frenulina, Dall. Sub-genus of Muehlfeldtia. Recent. 



FIG. 560. 



A, B, Kingena lima, Defr. Cretaceous; England. Lateral and frontal aspect of loop, enlarged (after 

 Davidson). C, Specimen from the Galeritenplaner of Salzgitter, 1/1- D, External surface, enlarged. 

 E, F, Kingena Friesensis, Sclmifer sp. Upper Jura ; Gruibingen, Wiirtemberg. 1/1- (c> Crura ; d, Dental 

 sockets ; e, Jugum ; /, I, Ascending and descending branches of loop ; j, Cardinal process ; r, Point of recurva- 

 ture of loop ; S, Median septum). 



Terebratalia, Beecher. Shell when adult like Terebratella, but passing 

 through a quite different series of metamorphoses. Recent. 



Dallina, Beecher. Elongate Terebrataliae with a small cardinal process 

 and a ventral median sinus. Tertiary to Recent. 



Macandrevia, King. Elongate Terebrataliae with dental plates and no 

 cardinal process. Recent. A sub-genus of Eudesia, according to Dall. 



Laqueus, Dall (Frenula, Dall). Like Terebratalia, but the loop has two 



Fio. 561. 



Lyra Neocomiensis, d'Orb. Lower 

 Cretaceous ; Morteau, Doubs. Natural 

 size. 



FIG. 562. 



A, Trigonoscmus elegant, Defr. White Chalk; 

 England. Interior of dorsal valve, enlarged (after 

 Davidson). B, T. Palissyi, Woodw. Upper Cretace- 

 ous ; Ciply, Belgium. Vi- (Drawn from nature.) 



lateral processes connecting the ascending and descending branches. Recent. 



Kingena, Davidson (Kingia, Schoenbach), (Fig. 560). Cretaceous ; Europe 

 and North America. 



Lyra, Cumberland 

 Europe. 



(Terebrirostra, d'Orbigny), (Fig. 561). Cretaceous; 



