HARPOCERAS VARIABILE. 455 



Gloucestershire. The diameter of this specimen is 225 millimetres. The body-chamber 

 is not complete up to the aperture, although it has left indications on the mould showing 

 the limits of its internal extent. The body-chamber occupies the whole of the last 

 whorl. The shell of the body-chamber appears to have been quite smooth, the whorl is 

 compressed and triangular, without carina and ribs, and on a portion of the penultimate 

 whorl the ribs have vanished, and the carina has disappeared. The suture-line is so 

 well preserved in the mould that it affords a safe guide for these observations. 



Affinities and Differences. — This Ammonite resembles Harp, variabile, by the series of 

 tubercles and fasciated ribs around the umbilicus. It is, however, a much thicker and 

 less elegant shell, and the whorls are likewise more rotund and not so high, the keel is 

 likewise much thicker and never attains the extreme elevation and remarkable structure 

 seen in Harp, variabile. Its ribs are likewise less flexed and the siphonal area much 

 broader in Harp, insigne than we shall find it to be in Harp, variabile. 



Locality and Stratigraphical Position. — This Ammonite forms one of the leading 

 fossils in the Lyt. Jurense zone in England. I have collected it at Frocester Hill, Sheeps- 

 combe, near Painswick, and at Ozleworth, all in Gloucestershire. 



Foreign Localities. — In France it is a common species in the Upper Lias above the 

 zone with Harp, serpentinum, and Harp, bifrons. According to Dumortier it is found 

 at Saint-Cyr, Poleymieux, Saint-Fortunat, St. Romain, Limas, La Verpilliere, Semur, St. 

 Julien, St. Nizier, Charnay, Fressac, Monies, Vaux; Fevroux, Ain ; Besancon, Thouars, 

 Mort, Charolles, St. Quentin ; and it is to be seen in the Museum at Lyons. In Germany 

 it lies in the uppermost stratum of the Upper Lias, the zone of Lyt. Jurense, near Hein- 

 ingen, Meiningen, Reichenbach, Hechingen, also near Uhrweiller-les-Vignes, Bas-Rhin. 



Harpoceras variabile, d'Orbigny. PL LXVII, figs. 1 — 6; LXVIII. 



Ammonites obliquatus, Young and Bird. Yorksh. Coast, p. 265, 1828. 



— Beanii, Simpson. Ammonites York. Lias, p. 36, 1843. 



— variabilis, d'Orbigny. Pale'ontol. Francaise, p. 350, pi. 1 13, 1842. 



— — Chapuis et Dewalque. Mem. Cour. Acad. Roy. Belgique ; 



Fossiles du Luxembourg, t. xxv, 

 p. 64, pi. ix, fig. 2, 1854. 



— — Oppel. Die Juraformation, p. 250, 1856. 



— dispansus, Lycett. Trans, of the Cotteswold Club, vol. iii, p. 5, 1865. 



— variabilis, Dumortier. Depots Jurass., partie iv, p. 77, 1874. 



Diagnosis. — Shell discoidal, compressed, carinated ; volutions one half involute ; 

 convex, transversely costated ; costae sigmoidal, inflated towards aperture, and fas- 

 ciated ; fasciculi arise from a tubercle situated near the inner margin, in general a single 



