500 Transactions of the Society. 



XXVIL— On a New Genus of Foraminifera (Aphrosina informis), 

 and Sjnculation of an unknown Sponge. 



By H. J. Carteb, F.E.S., &c. 



{Read 11th June, 1879.) 

 Plate XVIIa, Figs. 5-12. 



On the same specimeu of the coral of Amphihelia oculata wherein 

 Dr. Millar found Alectona Millari* I also found a species of 

 Foraminifera which I think must he considered the type of a new 

 genus. It had grown round a hole about three-quarters of an 

 inch in diameter formed by the sudden reunion of a branch which 

 had undergone division (Plate XVIIa, Fig. 5, d) ; and resembling a 

 bit of froth which consists of vesicles of different sizes, irregularly 

 spread abroad and heaped upon each other, I have designated it 

 thereafter, thus giving it the following name and description, vi2L : 



Aphrosina'^ informis, nov. gen. et sp. 



Amorphous, flat, spreading ; slightly convex and uneven 

 superiorly or on the free surface ; smooth and unil'orm below or on 

 the fixed surface, where it is attached to the object on which it has 

 grown ; margin thin and irregular. Composed of a great number 

 of vertically compressed chambers of different shapes and sizes 

 formed successively one after another, and sometimes one upon 

 another with the greatest irregularity, presenting on the surface a 

 number of convexities corresponding with the shapes and sizes of 

 the chambers below respectively (Fig. 6). Surface presenting a 



EXPLANATION OF PLATE XVIIa. Figs. 5-12. 



Fig. 5. — Aphrosina informis, n. gen. et sp. a, portion of tlie coral of Amphihelia 

 oculata ; b, hole formed by the reunion of the branch c ; d, Aphrosina informis in 

 situ. Natural size. 



Fig. 6. — The same. Diagram. Fragment of the surface to show its con- 

 vexities opposite the subjacent chambers, a, puncta representing hemispherical 

 tubercles ; 6, apertures on the margin. 



Fig. 7. — The same. Diagram. Vertical section to show — a, cavity of 

 chamber ; 6, intercaraeral aperture ; c, arch or upper wall ; d, floor or lower wall'; 

 ee e, manner in which the chambers are successively added. 



Pig. 8, — The same. Diagram. Fragment to show the apertures. 



Fig. 9.— The same. Diagram to scale of ^^ to -^~^, inch showing linearly — 

 a a a, the polygonal division and its pore tesselating the surface ; and bbb, the hemi- 

 spherical tubercles ; all relatively magnified both as to size and position. 



Fig. 10. — The same. Diagram of vertical section drawn to same scale, showing 

 — a a a, prismatic pillars and their tubes respectively ; 6 b'J), hemispherical 

 tubercles ; all relatively magnified both as to size and position. 



Fig. 11. — The same. Aperture, on same scale. 



Fig. 12. — Spiculation of unknown sponge, a, skeleton-spiciile; 6, bihamate j 

 c, equianchorate. Drawn to the scale of -^\ to -^Jj^-^ inch, and all relatively 

 magnified. 



* Vide preceding paper. t ^<Ppos, sea-froth. 



