Meyer — On Cretaceous Brachiopoda. 269 



criticised by Dr. Schloenbach, of Salzgitter (Hanover)' who states 

 that D'Orbigny's Terehratula Moutoniana possesses the short loop 

 of a true Terehratula. 



Such being the case the so-called " Waldheimia Moutoniana'' 

 figured by Mr. E. Eay Lankester in the " Greologist," vol. vi., 

 pi. xxi., figs. 1-4, and subsequently by myself in the Geological 

 Magazine (Vol. I., PL XII., Figs. 12-14), becomes a new species, 

 for which I suggest the name of Waldheimia Morrisii. 



1 append the following description : — 



Waldheimia Morrisii, sp. nov. (Geol. Mag., Vol. I., PI. XII., 

 Figs. 12-14).2 



Shell ovate or oblong-ovate, sliglitly tapering towards the beak. Valves convex, 

 deepest towards the posterior portion of the shell. Beak slightly incurved and 

 truncated by a moderately sized foramen. Beak-ridges sharply defined, producing a 

 slightly flattened hinge -area. Foramen semicircular above, pointed below where 

 completed by the two, almost triangular, plates of the deltidium. Larger valve 

 almost regularly convex, more abruptly so near the beak. Dorsal valve less equally 

 convex, much depressed at the sides, elevated in front, and sometimes exhibiting a 

 narrow longitudinal depression near the frontal margin of the shell, as in Terebratula 

 ovata, Sow. Loop much elongated, extending to near the front of the shell before 

 becoming reflected. Septum short and but slightly elevated. 



Length 10, width 7, depth 4|, lines. 



This species differs from Waldheimia celtica, Morris, in the com- 

 parative breadth of the valves, and still more conspicuously in the 

 curvature of the shell-margin, which in Wald. celtica is always 

 nearly straight. 



From Waldheimia tamarindus, Sow., its nearest 

 ally in the Greensand of Shanklin, it differs not 

 only in the size and proportion of its valves, but 

 also in the shape of the reflected portion of the 

 loop. 



From certain peculiarities observable in the 

 loop of Waldheimia tamarindus, Sow., Dr. Schlo- 

 enbach proposes (in the paper above referred to) 

 to place that species under the section Megerlia, Loop of an old specimen of 

 King. Yet after a long and careful examination ^Vaidf^- tamari?idus, sow. 

 of the interiors of a considerable number of specimens of Waldh- 

 tamarindus, I am unable to perceive that its loop ever approaches 

 sufficiently to that of a Megerlia, to warrant the removal of the species 

 out of the section in which it has been placed by Davidson. 



The arrangement of the loop and septum of Waldh. tamarindus (as 

 seen in examples from the Lower Greensand of Shanklin), may be 

 described as follows : — 



Loop elongated and recurved. The produced portions (lamelles ascendantes. Eug. 

 Desl.) extend (both in young and old examples) to very near the front of the shell 

 before becoming reflected. The reflected portions (lamelles recurrentes) return back 

 to about the middle of the shell, and form an arched or rounded loop, not unlike the 

 same portion of the loop in the recent Waidheimia cranium. — Miiller. 



In old specimens certain spinose projections occasionally make 

 their appearance on the sides and on the extreme front of the loop — 



^ Zeitschr. d. deutschen geologischen Gesellschaft, 1866. 



2 The numbering of Plates XL and XII. in Vol. I. of the Geol. Mag. was acci- 

 dentally reversed by the engraver. 



