222 



DE. C. T. TEECHMAXX OX 



[vol. Ixxiii, 



It comes from the east side of Mount Heslington, south of the 

 Wairoa Grorge, but there is no other fossil on the piece of rock 

 to indicate its horizon, which is probably Upper Carnic or Xoric. 

 I collected a rather weathered cast of a smaller dorsal valve in 

 felspathic sandstone in Bed a^ Otamita, Hokonui Hills, which is 

 probably Lower Xoric. 



Remarks. — Both this and the last species are remarkable for 

 the very naiTOw ventral area, the slight prominence of the venb-al 

 beak, and the fact that the apices of the wings end in acute points. 



Spirifeeixa dtomedea, sp. nov. (PI. XXIV, figs. 1 & 2.) 



Shell extremely alate, about live times as wide as it is long, the 

 wings narrowing gradually to the apices. The area extends the 



Fig. '^.— Gutta-perclia squeeze of tlie 

 interior apex of the ventral valve 

 of Spiriferina diomedea, sp. nov. 

 Bhcetic. South Hillencl, Otago. 



whole length of the wmgs : 

 it is broad and high, and 

 shows the comb-tooth struc- 

 ture along its whole length; 

 but Avhether the serrated 

 structure was exposed in 

 the living shell, or whether 

 during life it Avas covered 

 with an easily decomposable 

 layer of shell, I am not 

 able to say with certainty. 

 The ventral beak is blnnt, 

 wide, and rather prominent; 

 that of the dorsal valve is 

 broad, and projects very 

 faintly above the hinge- 

 line. The ventral valve 

 has a rather broad, shallow, 

 median sulcus, and on each 

 side three or four lateral sulci, only slightly smaller and no deeper 

 than the median one. The dorsal valve has a wide and low, 

 ti-iangular, rapidly-widening fold, Avhich extends to the beak, and 

 bears a slight median depression towards the anterior margin. On 

 each side are four narrower rounded folds of equal height, which 

 gradually decrease in size. The wings are free from folds towards 

 the apices. The delthyrium is wide, open, and triangular. The 

 median septum of the ventral valve is sharp but low, and extends 

 for about three-quarters of the distance to the anterior margin ; it 

 lies in a well-marked hollowed-out depression which accommodates 

 the muscle-scars, but these are not strongly marked. 

 Length = 26 mm. ; width = 127 mm. 



Locality and horizon. — The Xew Zealand Greological Survey 

 possesses a cast of a ventral valve in coarse felspathic grit, from 

 the north-western branch of Taylor's Creek, in the Hokonui Hills. 

 This form occurs plentifully in* the highest Trias with Hectoria 

 hisulcata at the southern end of Roaring Bay, Xugget Point, in 



"This shows the simken pit occupied by the 

 pedicle and muscle-scars and median 

 septum, also the area bearing- the 

 'comb-tooth' structure upon which the 

 subg-enus Eastelligeva was foimded.] 



