386 
ME. W. K. PAEIvEE AND PEOEESSOE T. E. JONES ON SOME 
D’Orbigny’s Asterigerina Plcmorbis (For. Foss. Vieii. pi. 11. figs. 1-3) supplies a very- 
good representation of this elegant form: see also Williamson’s Monogr. pi. 4. 
figs. 109-111 ( Rotalina Mamilla ), and his pi. 4. fig. 112, and pi. 5. fig. 113 ( B . ochracea). 
The most exquisite specimens of this variety are from San Domingo (fossil), where it 
abounds in the Miocene beds. It is always small ; but is larger and coarse on the 
Australian shores, passing insensibly into D. Turbo. It is common in the Grignon 
Tertiary deposits, rare in our Crag, and world-wide in the present seas. 
Discorbina Turbo , D’Orbigny, sp., Var. vesicularis, Lam., sp., Subvar. globularis, 
D’Orbigny, sp. Plate XIY. figs. 20-23 (Arctic). 
This small vesicular form of 1). Turbo , D’Orb., sp., is I). globularis , D’Orb., sp. 
(Modele, No. 69), from the Atlantic; and the same as Egger’s Bosalina semipunctata, 
Neues Jahrb. 1857, pi. 4. figs. 1-3. It is smaller than I). vesicularis , Lamarck, sp. 
(= 1 ). Gervillii, D’Orb., sp., Modeles, No. 72), and has fewer chambers. 
It is a world-wide form in shallow water and down to 70 fathoms, at which depth, 
west of the Bay of Biscay, it abounds ; it is, however, flatter here than when nearer the 
shore. In deeper water it becomes D. Berthelotiana and 1). rosacea , D’Orb., spp. 
At the Hunde Islands (Sutherland’s Soundings) it is large and rather common at 
from 30-40 fathoms; and middle-sized and common at from 50-70. 
Discorbina Turbo , D’Orbigny, sp., Var. vesicularis , Lamarck, sp., Subvar. obtusa, D’Or- 
bigny, sp. Plate XIY. figs. 18, 19 (Arctic). 
Discorbina presents a simple Botaline form of shell, usually having more or less vesi- 
cular chambers, with porous walls, and with the septal apertures in many cases guarded 
by flaps or plates, which sometimes form small secondary umbilical chambers. 
The specimen here figured is near to D. globularis , D’Orb., sp. (Modele, No. 69), but 
may either be regarded as a swollen condition of the beautiful D. Parisiensis, D’Orb., sp. 
(Modele, No. 38), or, rather, as D. vesicularis with the style of ornament characteristic 
of D. Parisiensis. The nearest approach to it among published figures is made by D. 
obtusa , D’Orb., sp., For. Foss. Yien. pi. 11. figs. 4-6. The coarseness of its pores, its few 
and subvesicular chambers, its large central chamber, and its peculiar ornamentation, 
are the chief characters of the variety before us. In the Arctic specimens the orna- 
ment appears as obscure, irregularly radiating, minutely granular lines on the lower face 
(not well shown in the figure] ; in D. Parisiensis the under surface has an exquisite 
sculpturing of minutely granulate lines or ridges ; D’Orbigny’s D. obtusa has a granular 
ornament in radiating'lines [not well shown in the figure]. D. globigerinoides, Plate 
XIX. fig. 7, a new variety of D. Turbo, also has this kind of ornament, being thickly 
covered on the septal plane with sinuous exogenous rugae, having large pores opening 
out of them, thus presenting a rudiment of the canal-system. 
At the Hunde Islands, D. obtusa is large and rare at 28 to 30 fathoms; large and 
rather common at 30 to 40 ; and large and common at 60 to 70 fathoms. 
