XArXILID^. 
191 
1871. Xatitihis striatus, Phillips, Geology of Oxford and the Valley of 
the Thames, p. 131. 
1872. XaidilKS striatus, Blake, Quart. Journ. Geol. Soc. vol. xxviii. 
p. 141. 
1875. Nautilus striatus, Phillips, Geology of Yorkshire, 3rd ed. pt. i. 
p. 2&3. 
? 1875. Nautilus annulark, Phillips, ibid. p. 263, pi. xii. f. 18. 
1876. Nautilus striatus, Blake, in Tate and Blake’s The Yorkshire Lias, 
pt. ii.. Palaeontology, p. 312. 
1878. Nautilus stnatus, Judd, Quart. Joum. Geol. Soc. vol. xxxiv.. Table 
facing p. 736. 
1881. Nautilus striatus, Gosselet, Esquisse Geologiqiie du Yord de la 
France, fasc. ii. p. 184. 
1882. Etheridge, Quart. Journ. Geol. Soc. (Proceed- 
ings — Anniversary Addi-ess), vol. xxxviii. p. 171. 
1883. Nautilus striatus, Hyatt, Ihoc. Boston Soc. Nat. Hist. vol. xxii. 
p. 302. 
1884. Nautilus striatus, L. Mallada, Bol. Com. del MapaGeol. de Espafia, 
vol. xi. Sinopsis de Fosiles de Espaua, p. 19 (tigured ibid. vol. v. 
1878, pi. hi. f. 3). 
1888. Nautilus striatus (?), Beeby Thompson, The Middle Lias of North- 
amptonshire, p. 54. 
Sii. Char. “ Slightly depressed ; umbilicate ; concentrically stri- 
ated ; aperture half the diameter of the shell, nearly orbicular.” 
{Soiuerbi/.) 
Remarl's. To the above short description Sowerby adds the fol- 
lowing : — Whorls rather gibbose, they are few, and increase 
rapidly ; the umbilicus is large, exposing a small part of the inner 
whorls ; the numerous striae which cover the surface are irregular, 
elevated, and so strong that they might almost be considered as 
ridges ; the front is a little compressed, giving the aperture a 
squarish form.” 
Dumortier states that this species is found pretty abundantly in 
the “ Ammonites BucTdandi zone,” in the Lower Lias of the Bhone 
Basin ; but it is badly preserved. 
Chapuis {loc. cit.) adopts the name Nautilus aratus (Schlotheim) 
for this species, and (following Quenstedt) distinguishes three varie- 
ties of it, A, B, and C ; the first (A) being the Nautilus striatum, J. 
Sowerby, the second (B) Nautilus semistriatus, d’Orbigny, and the 
third (C) Nautilus intermedius, J. Sowerby. But the characters 
distinguishing these three forms may well be regarded as of specific 
value. The present species differs from N. intermedius and N. 
semistriatus by its uniformly rounded and uncompressed whorls, and 
again from the last-named species by its larger umbilicus and per- 
sistent striae. 
