SONNINIA SPINEA. 405 



/3. Costation regular. 

 1. Correlated umbilication considerable. 



Sonninia euromphalica, 8. Buchnan. See Plate LXXXV, figs. 1 — 3, and page 362. 

 Sonninia omphalioa, 8. Buchnan. See Plate LXXXIII, figs. 5 — 9, and page 363. 



2. Correlated umbilication not so considerable. Ornament rather less. 

 Sonninia spinioostata, S. Buchnan. See Plate LXXIII, figs. 4 — 6, and page 337. 



Add to description : — Suture-line with short lobes ; L broad-stemmed and short, 

 its terminal lobule intra-axial, anisosecloid, inequicellate ; its lateral lobules some- 

 what anisometric. 



[Note. — In the text relating to this species (p. 337) the words " spines " and 

 " spinous " are used in a general sense to include the knobs. The necessity for the 

 distinction between spines, bullse, and nodi had not then been felt, but it afterwards 

 became imperative to introduce precise terms. The spinous stage, which is often 

 mentioned in this work, included all tuberculated sub-stages — all stages when the 

 costas possessed anything like what the Wessex man calls " a rising." In future 

 all these sub-stages may be advisedly united as the " tuberculate stage," and this 

 stage may be "spinous," " spinicostate," " bullicostate," or " nodicostate." 

 Further, in some forms to be treated later the nodus or bulla may be " sessile," — 

 that is, without any costa to support it ; or it may be " pedigerous," — that is, 

 carried on a costa or costae ; literally " bearing a foot, or feet."] 



A strict consideration of the septal details of this species in comparison 

 with those of costata and parvicostata shows the necessity for its removal. 

 These details agree so closely with those of species now placed in connection 

 with this one, that there can be little doubt as to the present being its correct 

 position. 



Sonninia spinea, 8. Buchnan. Plate LXXXVI, figs. 4 — 6. 



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

 spines to about 40 mm. shell-diameter, with spinicostse and costse roughly alternate 



