XArTILID^. 
215 
1873. Xaidilus polyffonalis, Sharp, Quart. Jouru. Geol. Soc. vol. xxix. 
pp. 294, 299. 
1890. Nautilus polygonalis, Foord and G. C. Crick, .4.nn. k, 31ag. Nat. 
Hist. ser. 6, vol. v. p. 222, f. 4. 
Sp. Char. “ Sphaeroidal, compressed, smooth ; columella promi- 
nent ; umbilicus very small ; aperture arcuate, above half the 
diameter of the shell, long ; septa distant ; siphuncle near the outer 
edge of the septum, composed of a number of straight tubes. The 
thickness of this is about two thirds of its diameter ; it has a large 
aperture, the reflected extremities of which nearly close the umbi- 
licus ; the septa are distant, very concave, and but slightly curved 
at their edges ; the siphuncle consists of a number of straight tubes, 
each projecting a little behind the septum it pierces to join the pre- 
ceding tube. The whole series appears to be disjointed ; the 
polygon formed by it in the section has suggested the specific 
name.” {Soiverhy.) 
llemarlcs. This species is distinguished from N. lineatus, which it 
closely resembles, by its less numerous septa, with their strongly 
sinuous sutures, and by the position of the siphuncle. 
The impression of the shell-muscle is well shown in one of the 
specimens in the Collection (No. C. 2847), and is indicated in fig. 43. 
It is very similar both in form and position to that of the recent 
Nautilus. 
Horizon. Inferior Oolite. 
Locality. Halfway House, Dorsetshire ; Dundry, Somersetshire. 
Sowerby states that his specimen is “probably from Dorsetshire.” 
The localities of other specimens in the Collection are not known, 
but they are undoubtedly British. 
Well represented in the Collection, which contains (“ Sowerby 
Collection ”) J. de C. Sowerby’s figured type. 
Nautilus glaber, Foord and G. C. Crick. 
1890. Nautilus glaber^ Foord and G. C. Crick, xlnn. & Mag. Nat. Hist, 
ser. 6, vol. v. p. 278, f. 10. 
Sp. Char. “ Shell completely involute, slowly increasing in dia- 
meter, compressed laterally, flattened on the periphery. Whorls 
wider than high, widest just above the umbilical region. Umbilicus 
completely closed. Septa moderately distant, shallowly concave ; 
the sutures strongly bent backwards on the sides and very slightly 
sinuated upon the periphery. Siphuncle situated markedly above 
the centre. Surface of the test quite smooth. Body-chamber 
