22S DR. c. T. TEEciiiiAXx OX [vol. Ixxiii, 



Piroutet records three Alpine species of Betzia from the Trias of 

 New Caledonia, of which R. aff. auperhescens is the onh^ one that 

 resembles the present form. 



Mextzelia cf. AMPLA Bittner. (PL XXIII, fig. 9.) 



1890. ' Bracliiopoden der Alpiiieii Trias ' p. 165 & pi. xH, figs. 10-11. 



Yentral valve inflated, the dorsal rather less so, area triangular, 

 rather high, less than the width of the shell, the ventral beak 

 somewhat bent over it. The ventral valve has a broad and 

 shallow romided sulcus, which does not continue to the apex. 

 The dorsal valve bears a rather broad, rounded, triangular fold, 

 which does not reach the beak and is bordered on both sides by 

 steep slopes. In the ventral beak there is a sharp median septum 

 with sharp dental plates on each side of it. The shell-structure 

 is* fibrous, and at the same time faintly punctate. 



Length =81 mm. ; width zz 42 mm. ; thickness = 20 mm. 



Locality and horizon. — I collected a single specimen in 

 pebbl}^ sandstones, with Arcestes cf. rhcdticus and Hectoria 

 bisulcata, several hundred feet above the Pseicdomonotis-ocJiotica 

 Beds, north of Albatross Point, Kawhia. The wings of this speci- 

 men are damaged, and the ventral beak is slighth^ eroded. Bhsetic. 



Be marks. — This smooth JSlentzelia seems to agree closely with 

 the above-named species, which Bittner thinks may be a variant 

 of the Muschelkalk form JLT. mentzeli. In the Alps M. ampla 

 occurs at a horizon corresponding to that of the St. Cassian Beds ; 

 while the typical JSL mentzeli is predominantly a Muschelkalk form, 

 but has been found also in the Carnic of Spiti in the Himalaj^as. 



Mextzelia kaw^hiaxa, sp. nov. (PI. XXIII, figs. 10 « & 10 i.) 



Shell rather wider than long, the anterior margin gently rounded. 

 The ventral valve is somewhat swollen and arched, the beak tapering 

 gradually, the dorsal valve is almost flat, and the margin of the 

 valves lies nearly in one plane. The area is less than the width of 

 the shell, and seems to have been rather high. The ventral valve 

 has a shallow, rounded, rather broad, median sulcus, with about 

 seven very faint and narrow, lateral, I'ounded ribs on each side of 

 it : these do not continue to the beak, and are absent from the 

 lateral jDortions of the shell. The dorsal valve bears a very faint, 

 flattened, triangular, median fold and about seven verj^ faint, narrow 

 ribs on each side of it which do not reach the beak. The lateral 

 portions of the shell towards the hinge-area are smooth. 



Length==:25 mm. ; width = 31 mm. 



Localit}" and horizon. — I collected a single specimen not far 

 from the last-described form in the Arcesfes and Hectoria Beds, 

 in the cliff- section south of Kawliia Harbour. Ehaetic. 



Be marks. — The shell-structure is fibrous and faintl}^ punctate. 

 This form i-ather closel}^ resembles M. jyaJcEoti/pus Loretz, from 

 the Alpine Muschelkalk, but has fewer radial ribs, a weaker dorsal 

 fold and ventral sulcus, a more prominent beak, and a less inflated 

 Ahell. 



