6 
NATJTILOIDEA. 
1880. Litiiites i^erfectus, Kjerulf & Gurlt, Die Geologie des siidlich. 
imd mittl. Norwegen, p. 68. 
1880. Lituites lituus, Angelin & Lindstrdm, Fragnienta Silmica, p. 8, 
tab. ix. f. 8. 
1881. Lituites lituus, Scbroder, Beitrage zur Kenntn. der in ost- und 
westpreussiscben Diluvialgescbieben gefundenen Silurcephalo- 
poden, in Scbriften der physiic.-okonom. Gesell. zu Konigsberg, 
Band xxii. Abth. i. p. 58. 
1882. Lituites lituus, Noetling, Zeitscbrift der Deutscb. geol. Gesell. 
Band xxxiv. Heft i. p. 156, Taf. x., xi. 
1883. Lituites lituus, Noetling, Jahrb. der Konigl. Preussiscb. geol. 
Landesanst. und Bergakad. zu Berlin f. d. Jahr 1883 (1884), p. 129. 
Char. The shell is at first discoid, the whorls about four in 
number, having an oval transverse section, contiguous (?), slowly 
increasing in diameter, afterwards produced into a long straightened 
piece, which is, however, slightly curved for a short distance after 
freeing itself from the coiled part. The rate of increase of the 
straightened part is about 1 in 8. The thin test consists of two 
layers, and the varying strength of the lines of growth gives it a 
wavy appearance, the outlines of the successive apertures being 
marked by a series of undulations, which are strong enough to leave 
their impress upon the cast. Finer lines of growth cover the whole 
of the test. The undulations form a shallow sinus on the ventral 
side of the shell, and project forwards on each side, thus producing 
lateral “ saddles ” which, increasing in height towards the aperture, 
there form two lobes or projections inclined towards each other, as 
seen in some Ammonites h The aperture is thus contracted, and 
presents a bifoliate figure when viewed from above. The septa are 
simple ; about twelve may be counted in half a volution of the 
spiral part, when the diameter of the latter is 9 lines. The distance 
of the septa gradually increases with the growth of the shell. The 
body-chamber is 3 inches long in a specimen 11 J inches in length ; 
its basal diameter is 13 lines, its apertural 18. The siphuncle is 
central in the coiled part of the shell, untB the last whorl is reached, 
when it begins to take up its normal position, which is maintained 
throughout the straightened portion of the shell : this position is 
about 5 of the distance across the dorso-ventral diameter, in the 
median line ; it is scarcely infiated between the septa. The dimen- 
sions of a fine and nearly perfect example of this species, figured by 
rToetling (loc. cit. 1882), of the natural size, are as follows : — 
greatest diameter of the coiled part of the shell 10 lines, greatest 
^ A. Jason, e. g. 
