538 



THE INVERTEBRATA 



m-d, stk. 



Fig. 397. Longitudinal section of Magellania (Waldheimia) slightly to the left 

 of the middle line. After J. J. Lister, bzv. body wall; di.gl. digestive gland; 

 h. heart; int. intestine; Ip. dorsal hp of Iph. lophophore; M. mouth; 

 m.d. muscles running from dorsal valve to ventral; nphr. nephrostome; 

 ri. vertical ridge on dorsal valve; st. stomach; stk. stalk; tn. tentacles of 

 lophophore; tn.t. terminal tentacles. 



Fig. 398. Fig. 399. 



Fig. 398. Terehratula semiglohosa, Upper Chalk. A, Dorsal; B, Lateral view. 

 a, posterior; b, anterior; a-h, length; c-d, breadth; e-f, thickness; ^^-A, hinge 

 line, X f . From Woods. 



Fig. 399. Vertical section of shell of Magellania {Waldheimia) flavescens. 

 a, prismatic layer; b, periostracum ; c, outer calcareous layer; d, e, canals 

 traversing the calcareous layers, containing the mantle papillae in life. 

 After King. 



