434 INFERIOR OOLITE AMMONITES. 



Sonn. renovata is certainly very rare. The preservation of the adult shell 

 suggests that it occupies a position at the very top of the Concavum-zone, — that is 

 to say, it is associated with Hyperlioceras discites, &c. 



Since the above remarks were penned, Mr. J. W. Tutcher, of Bristol, has found 

 at Dundry a large specimen, 257 mm. in diameter. It agrees in umbilication and 

 dimensions exactly with the type, and in ornament is almost spine for spine the 

 same. Its septa show exactly the same asymmetry of L, while the terminal 

 lobule is anisosceloid and intra-axial in the same manner as in the type ; but the 

 septa are rather closer together, and the superior lateral saddle is therefore more 

 penetrated by lobes. The only observable external differences — and one of these is 

 partly due to inferior preservation — are a slightly greater reclination of the costae 

 in some places, and a less degree of spinosity in what corresponds to the outer 

 whorl of the type. 



The specimen shows half-a-whorl more than the type, all of which is body- 

 chamber, ornamented with somewhat reclinate bullicostae. Mr. Tutcher very 

 generously presented this specimen to my collection. It was sent to me as from the 

 Concavum-zone, and judging by its matrix it occupies exactly the same position as 

 the Dorset specimen, namely, the top of the beds with Hyperlioceras. 



Sonn. renovata is figured in PL XCIII : fig. 1, side view of the type, reduced 

 to two-thirds of natural size ; fig. 2, the outline of the whorl-section, similarly 

 reduced ; fig. 3, septal outlines ; fig. 4, a young specimen, of natural size, before 

 the remarkable metamorphosis ; fig. 5, its outline front view ; fig. 6, its suture-line. 



Sonninia reformata, 8. Buckman. Plate LXXXIX, figs. 6 — 8. 



Discoidal, compressed, hollow-carinate. Whorls ornamented with spines, 

 subspinicostae, and costae : regular spines to 18 mm. diameter of shell ; then plain 

 costee ; then costae and subspinicostae alternate, or as 2 to 1 — the spinicostae trifur- 

 cate beyond the spine — to 45 mm. diameter ; lastly, direct, somewhat numerous, 

 somewhat irregularly-sized, reclinate, ventrally-inclined costae. Ventral area 

 arched, somewhat flattened, divided by a fairly-defined hollow carina, the core 

 carinate-bisulcate, the sulci fairly-marked. 1 Inner margin ill-defined, subconvex, 

 steep. Inclusion about two-fifths, allowing for carina. Umbilicus graduate, con- 

 centric. Whorl-section suboval. Suture-line with long and ornate lobes ; L with 



1 The figure shows the ventral area without test -a ventral area with a distinct carina. Remains 

 of the partition-band and of the walls of the hollow carina are on other parts of the periphery, and 

 they indicate the size of the true carina. 



