133 
REPORT- 1847 * 
radiated arrangement. Magnified 162 diam. 80).—Fig. 35. Section 
of shell of Pandora rostrata^ traversing the external layer of prismatic 
cellular structure (a), and the internal nacreous layer (b). Magnified 
400 diam. (§ 86).—Fig. 36. External layer of Sokmya australis, shn- 
iug lung prismatic celH whose a.\e8 are nearly parallel to the suriict 
Magnified 53 diam. {§ 84). 
Plate LX.—Figs. 37 and S8. Section of the shell of Solemya austraiu, 
passing obliquely from externa! surface (a) to internal surface (c), md 
showing gradual transition from cells with firm membranous walli (oM 
to cells wlinse are lesa distinct (ce)> nod at last into a stroctuR 
(de) ill which the traces of the partitions almost disappear. .Magnified 
40 diam. (§ 8t).—Fig. 39. Decalcified mc.nibraue of the eslernal li)«r 
of the same shell (fig. 36). iMagnified fiO diam. (§ H) —Fig. 40. .h- 
other portion of the internal layer of the shell of Solmya atalrdu, 
composed of distinct priainalic cells. Magnified 60 diam.(§ 84). 
Plate X. — Fig. 41. Extt’rrmI surface of »S’o/c» (beneath the epiiii’miisl- 
showing the rounded terminations, with dislincl nuclear spots, oflbf 
long prismatic cells of which tlie external layer is composf^. Magm- 
fied 150 diam. (§. 84 ).. — Fig. 42. Internal layer of Solecurtus, shoiriM 
traces of cellular amiiigement. Magnified 150 diam. (§ 81).— 
External layer of Soten, showing long prismatic cells with transvf® 
striffi.—(N.I j. Tlic linos of division between tlie cells, which 
zontalljf in this figure, are not inarkeil M ith sufficient clearness; 
the verticaJ lim^, whieli indicate the successional growth ami ebugatiou 
of the ]irisiuatic, or rather fusiform, cells, are rather too foreilily*’ 
pressed.) Magnified 55 diam. (§ 84).—^Fig. 44. Outer layer of .Si?®- 
ria giganteo, as shown in a vertical section of the tube, following it> 
surface. ^ Magnified 40 diam. (§ 85).—-Fig. 45. Section of iuner lar« 
of ditto in the same direction. Magnified 40 diam. (§ 81). 
Plate XL—Fig. 46. Transverse section of tube of Stptaria gigank-^^ 
ing the thin outer layer (ri), the thick iniuu- layer (6), and thesncc^ 
ive addiuoiis subsequently made to its intemiJ surface at r. 
20 diam. (§ Sti). — Fig. 47. Portion of fractured surface of middle 
of Cgprtva muuritiana, broken transvomdy to the liries of growth; dio#- 
niglamimii composed of prismatic cells obliquelv crossing each oWff- 
From u figm^ of Mr. Ilowcrbank s. Magnified' 235 diam. (§ SO}-- 
Fig. 48. Section of shell of Cypnm mauritiana^ in the same direc^ 
showing prismatic appearance of externa! laver (o), andofibdophes^ 
(d); laiuime of internal layer (5) crossing obliquely; and prisnia^uc 
pearance of internal layer (c). Magnified 125 diam. (§ 91 
Section of Co/m# in the same direction, sbowing the reverse appear^ _ 
namely, prismatic appearance of middle layer (ft), and obliquely^ 
sechng tamma of external layer (a) and of internal layer (r). 
bed 70 diam. (6 91V ^ ^ ' 
.1 ' *< “**'" uuuuie layer i^O), arranged at ngtit ,ia/ 
other. Magnified GO diam. (§ 92).--Fig. 51. Vertical section of shell 
Patella, nearly parallel to the surface, traveling the middle layer 
compused of polygonal celU cut ti-ansverselv, and the internal Iflyerl^’JjJ 
whose irregular pri.smatic cells are cut longitudinallv and shown 
i /s Eitprual »y*‘ 
