Mr. H. J. Carter on the Polytremata. 213 



or ends of" pillars of support iu foraminated groundwork : /( h, un- 

 foraminated linear arete uniting the same ; i, larger dimples or 

 circular arese, foraminated in the centre and surrounded by au 

 imforaminated ring; k, subhexagonal or poh'gonal unforaminated 

 reticulation, -with foraminated interstices ; I, tine linear (tubular ?) 

 network in centre of unforaminated reticulation ; m m m, threads 

 composed of an agglomeration of sand, siliceous spicules, and 

 other minute objects, connected with the apertures and with 

 each other ; n n n, spicules projecting from the apertures of 

 the entire branches; ooo, the same, projecting from apertures 

 formed iu the ends of the branches broken off; /p, triradiate 

 spicule arrested in an aperture ; q, purple spicule of a Gvryotiia ; 

 »•/•, globo-stellates of a Compound Tmiicated animal; 55, dried 

 pseudopodia ; t t, cancellated structure of interior ; v v r, cavities 

 in the same, containing spicules chiefly in a fragmentary con- 

 dition. 



i'Vy. 7. Pohjtrema halnniforme, Carter ( Carpenteria, Gray), on a valve of 

 Mytilicardia calyculata, nat. size : a, a, apertures. 



N.B. For good illustrations of the test of this species, see 

 Car|)enter, ' Phil. Trans.' 1800, vol. cl. pt. 2, pi. xxii. figs. 1 and 

 5-15 ; also ' Introduction to the Study of the Foraminifera,' 

 1802, pi. xxi. figs. 6-18, but not so well executed. 



Fiy. 8. The same. Supposed embryo, about l-92nd inch long : a, apex ; 

 b, base ; c, chitinous integument, micro-gi'auulated ; cl, large 

 spiral apertm'e ; e e, small papillaiy apertures ; /, one of same, 

 from which a minute filament of foreign substance is projecting ; 

 y, internal caviiy, surrounded by opaque granular material, ap- 

 parently in pouch-like cavities. Scale about l-12th to l-8y0th 

 of an inch. 



Fiy. 9. The same, embryos of (?), on fragment of cancellated cavity 

 from near circumference : a, lobed form, l-332nd inch in dia- 

 meter ; bbb, unlobed smaller forms. Scale l-12th to l-830th 

 of an inch. 



Fig. 10. The same. Sponge-spicule ; new furm of bihamate or fibula, 

 from among spicules of the interior, l-2o0th inch long. Lower 

 end restored. 



Fiy. 11. Pohjtrema tdriculare, n. sp., gi-oup of three individuals, nat. size. 



Fiy. 12. The same, superior view, magnified : a, utricular bodies ; bb b, 

 apertures ; c, polygonal reticulation of surface. 



Fiy. 13. The same, lateral view, magnified : a a a, apertures at the ends 

 of neck-like prolongations of the tests respectively. 



Fiy. 14. The same, basal view, from which the sarcodic (now chitinous) 

 layer at once of occlusion and attachment has been removed, 

 showing : — a a a, cavities of the three individuals respectively, 

 each of which is filled with fragments of spicules, as represented 

 mh; c, wall at base of test, .showing relative position and size 

 of polygonal reticulation and furamiuated layers respectively; 

 d, apei-tures on internal aspect of foraminated layer; e, sarcodic 

 (now chitinous) layer lining the utricular chfauber and prolonged 

 into the apeilure — reflected. 



Fiy. 15. The same, fragment of surface, magnified, to show, o, polygonal 

 reticulation, and, b, foramina at the bottom of the mterstices 

 respectively. 



Fiy. 10. Tlie same, vertical section of wall of test, to show relative 

 position and size of polygonal reticulation, «, and foraminated 

 iavcr, b. 



