Foraminifera /row the Coast of Norway. 279 



thalamous Foraminifera selected from the Norway dredgings, 

 aud here figured, for the purpose of showing the wide variations 

 of shape and size presented by these shells, and every gradation 

 between which is met with among specimens from this and other 

 sources, including recent and tertiary deposits. 



Fig. 22 presents the long-necked, flask-like, typical form of 

 Layena^ ; and figs. 23 & 24 are two of its varieties : in fig. 23, 

 the convexity is less than in fig. 22, the base is elongate, and 

 the neck is rimmed : in fig. 24, the body of the "fiask" is still 

 more cylindrical, the neck is shorter, the surface has several 

 parallel ribs, and the base is perforate. This extreme variety 

 of form (fig. 24) is related, by endless intermediate variations 

 (including fig. 23), with the gibbous form, fig. 22. Fig. 27 is 

 a ribbed Entosalenia, and is vastly more gibbous than fig. 24, 

 being almost globular ; it is numerously and deeply ribbed, and 

 is thickened around the aperture with a frill of four equal obtuse 

 angles. Fig. 26 differs from the last in having its less numerous 

 ribs united by small transverse ridges, and in having its neck 

 less thickened and shorter. In fig. 25 the superficial ornament 

 is formed of hexagonal meshes, as if the ti'ansverse and longitu- 

 dinal ridges had been equalized and combined into a reticulation . 

 These three forms (figs. 25 to 27) are also in every respect linked 

 together by numerous recent and fossil varieties, and gradually 

 pass, by insensible gradations of external character, into the 

 elongate varieties of Lagena, such as figs. 22-24. 



Figs. 28 aud 29 represent the common, somewhat flattened, 

 margined, round and oval varieties of Entosalenia-f, which, by 

 losing their keels, becoming globose J, and being provided with 

 an external instead of an internal tube, closely represent the flask- 

 shaped Lagena represented by fig. 22. They are very subject 

 to ornamentation of riblets and reticulation (figs. 25-27), and, 

 excepting by means of the characteristic usual internal tube, 

 are scarcely divisible from Lagena. Still, however, there is a 

 peculiarity in the setting-on, as it were, of the tubular neck in 

 the externally-tubed individuals referred to, which appears to 

 permanently distinguish Entosalenia from Lagena. From the 

 very minutely-marked gradation of diff"erences between indi- 

 viduals, even in the same sample of sea-sand (recent or fossil), 

 it is extremely difiicult to speak of anything like specific cha- 

 racters among the endless varieties of Lagena and Entosalenia 

 presented to the observer. 



Marine sands from Shetland, Skye, Pegwell Bay, Eastbourne, 

 Australia, Bombay Harbour, &c., also the post-tertiary clay be- 



* Oolina clavata, D'Orb. For. Foss. Vien. pi. 1. f. 2, 3. 



t 0. coinpressa. D'Orb. Vov. Amer. Merid. vol. v. part 5. pi. o. f. 1, 2. 



+ 0. glohosa, D'Orb. ih. f. .3. 



