192 DE. C. T. TEECHiIAX]S" OX [vol. Ixxiiiy 



they possess an anterior byssal notch in the right A^alve, which is 

 wanting in the true 31. salinaria^ was pointed out by Tener,^ who 

 consequently placed them in the genus Pseudomonotis. 



I haye found this bj'-ssal ear and notch in all the New Zealand 

 specimens that I examined, except in those that occur in lime- 

 stone at Okuku. In some cases the I'ock must be carefully cut 

 away to show it ; but it is always present, except in the case just 

 mentioned. In the large flat A'arieties of Pseudomonotis ochotica 

 the ear and notch are reduced to the smallest possible size. 



F. Freeh 2 thinks that the three circum-Pacitic species of Fseitdo- 

 monotis: namely. IPs. ocliotica, JPs. richmondiana, Siud I^s. siih- 

 circiilaris, are yarieties of one and the same shell. He believes that 

 JPs. richmondiana occurs in two forms, and figures and describes 

 a new form as yar. iruncata, pointing out its resemblance to 

 -Ps. ocliotica yar. sparsicostata. He also considers Ps. suhcir- 

 cidaris identical wnth Ps. ocliotica yar. spai^sicostata. 



Ps. riclimondiana has been recorded only from New Zealand 

 and New Caledonia. Ps. stihcircularis is a British Columbian, 

 Calif ornian, and South American Cordilleran form, and characterizes 

 the Noric Beds. Ps. ocliotica was first discoyered at Verkhoj^ansk 

 in Arctic Siberia, in beds of Noric age. It was found later in 

 Japan, 3 where it occurs in beds yery near the top of the Trias 

 and a yery short distance below the oyerlying Jurassic. It is also 

 recorded from Central Timor, where a specimen of Ps. ocliotica yar. 

 densistriata was found in a pebble in the Talau Riyer.'* 



I now record Ps. ocliotica, as defined by Teller, for the first time 

 in New Zealand. It is a yery yariable species, but an eyen greater 

 range of yarieties is present among my specimens than among 

 those from Arctic Siberia figured by Teller and Mojsisoyics. 



Near the head of Garden Gully, on its western slope a mile 

 south-west of the Wairoa Gorge, in the Nelson area, I was for- 

 tunate in finding a bed of fine-grained dark greywacke-mudstone, 

 containing a large series of forms which undoubtedly belong to the 

 Asiatic fossil Ps. ocliotica. The beds seem to occupy the middle 

 limb of a syncline, or possibly a faulted syncline of the Trias, and 

 are, I think, the highest Triassic rocks exposed in the Nelson 

 district. In this district the yarieties of Ps. ocliotica occur in the 

 bed in Garden Gully to the exclusion of Ps. riclimondiana. The 

 typical Ps. riclimondiana occurs in yast numbers in a bed exposed 

 some distance away on the opposite slope of the yalley to the east; 

 but the two forms are clearly separated, and I haye little doubt 

 that Ps. riclimondiana occurs at a lower horizon than Ps. ocliotica. 



The felspathic sandstone at Richmond, 5 miles north-easfc of 



^ Bibliograpliy, 35, p. 104. It is clear that the genus Pseiidomonotis does 

 not represent a natural group. The Psendomonotis forms of the Upper Trias 

 are much more closely related, to Monotis salinaria than they are to shells 

 called Pseiidomonotis in the Permian or Jurassic, such as Ps. speUincaria or 

 Ps. echinata. 



- Bibliography, 13, pi. Ixvii:. 



^ Bibliography, 33, p. 175. ^ Bibliography, 49, p. 189. 



