part 3] jueassic rocks of new Zealand. 271 



Pseudomonotis cf. echinata Sowerby. (PI. XIII, figs. 14 & 15.) 



Description. — Left valve swollen, about as wide as high, the 

 lower and posterior margins rounded. Numerous fine ribs start 

 from the beak, and pass to the margins ; they are cut by the 

 growth-lines into very small foliaceous nodes. The posterior wing 

 is wide and rather flattened, the anterior less so. The right valve 

 is subcircular in outline, rather longer than high, the posterior 

 wing flattened, while the surface is well rounded and apparently 

 smooth. 



Dimensions. — Left valve = 10 mm. in length and nearly 

 10 mm. in height. Eight valve = 8 mm. in length and 7 mm. 

 in height. 



Locality. — A slab of sandstone, with casts of both valves on 

 it from which gutta-percha squeezes were made, comes from the 

 stretch of coast between Nugget Point and the Catlins River. 

 The exact locality is not stated : but the locality-number is 801, 

 and the specimen belongs to the New Zealand Geological Survey. 



Remarks. — This shell is very nearly related to, if not identical 

 with, the well-known European Lower Oolite form. On comparing 

 the squeezes with a number of specimens from the Cornbrash of 

 Wiltshire in my collection, I can find no important points of 

 difference. If it is identical, it forms an interesting instance 

 of extended distribution of a common shell, the more so as some 

 palaeontologists hold the view that a form allied to this shell was 

 the ancestor of the Aucellce. 1 It has been recorded from the 

 marine Jurassic of Western Australia. 



Oxttoma sp. (PI. XII, fig. 9.) 



Description. — Shell small, inflated especially in the umbonal 

 region ; the beak scarcely projects above the hinge-line, which is 

 straight and prolonged into an acute posterior wing. There is a 

 small anterior wing in front of the beak ; the anterior margin is 

 nearly straight, the lower is rounded, and the posterior margin 

 rather produced. The decoration consists of about 24 straight or 

 very slightly curved radial ribs, which do not seem to continue to 

 the beak. 



Dimension s. — Length = 13 mm ; height = 11 mm. 



Locality. — Junction of Taylor's Creek and the Otapiri. 

 Psiloceras Beds. 



Remarks. — This small aviculoid shell rather resembles in 

 outline and ornamentation Pseudomonotis munsteri Bronn, of 

 which a left valve is figured by Gottsche from Espinazito. 

 P. munsteri is, however, a Lower Oolite shell, while the present 

 example, a left valve, is from the lowest Lias. The ribs in the 

 present shell seem, however, to be smaller and more numerous. 



1 J. F. Pompeckj, ' Ueber Aucclleii & Aucellen-ahnliche Pormen ' Neues 

 Jahrb. Beilage-Banci xiv (1001) p. 337. 



