KINGENA. 



41 



the lamellae extend again to about two thirds of the length of the valve ; when, bending 

 back upon themselves, they form a large wide loop, and, after leaving a very small 

 free space just above the septum, are likewise fixed on either side to the central septum 

 above the under pair. 



Obs. The remarkable character and disposition of the lamellae in this form, induces me 

 to propose a subgeneric title, as such shells could not with propriety be placed in any of 

 the sections now in use; and to afford greater facilities of comparison, I have introduced 

 some illustrations of different sections of the family Terebratulidce : 



Fig. l. 



Fie. 2. 



Fig. 3. 



b a 



Fig. 4. 



Fig. 5. 



Fig. 6. 



Fig. 8. 



Figs. 1 and 2 represent the interior of Terebratula Australis : in this the loop is simply 

 attached to the crural base, the riband-shaped lamellae forming throughout a free and 

 slender loop, extending into the cavity of the valve. 



Figs. 3 and 4, Terebratella Chilensis: here the loop is doubly attached, first to 

 the crura, then again to the central longitudinal septum, before proceeding forth, and 

 bending back, to form a free slender loop, as in Terebratula. 



Fig. 7, Megerlia truncata : a slightly elevated medio-longitudinal crest proceeds from 

 under the muscular fulcrum {a) to less than half the length of the valve, near the extremity 

 of which {ff) two short central diverging branches arise (n) and support the calcareous loop, 

 which consists of two riband-shaped lamella first attached to the inner side of the socket 

 walls or crural base, afterwards extending to the extremity of the diverging branches (n) to 

 which they are affixed before proceeding on both sides in the same direction to their 



