418 THE LIAS AMMONITES. 



fimbriatum, but it is distinguished from that and other congeneric forms by its large 

 convex ribs and deep valleys, and by the well-defined striations which adorn the convex 

 surface of the ribs, whilst it wants the longitudinal striae that are seen on the shells of 

 Lyt. fimbriatum and Lyt. cornucopia; it is evidently a well-marked species of the 

 group to which it belongs. 



Locality and Stratiyraphical Position. — I have only seen fragments of a mould referred 

 to this species in connection with the Harp, opalinum-hed at Frocester Hill, Chideock 

 Hill, and Burton-Bradstock, near Bridport, Dorsetshire, associated with Harpoceras 

 opalinum. Turbo capitaneus, Gervillia lata, BhyncJionella cynocepliala. This bed forms a 

 thin stratum, rich in many well-preserved specimens of these moUusks. 



Foreign Distribution. — The Torulosum-zone is very well exposed in many parts of Ger- 

 many ; the type specimen oiLyt. torulosum was found at Stufenberg. Professor Quenstedt 

 collected it at Gomaringen, Aselfingen, and Wutzch. In the vicinity of Kloster Banz a 

 considerable number of the leading fossils of this zone have been collected, and many of 

 them were figured in Goldfuss. It has been carefully described by Professor Lepsius in 

 his ' Unter Elsass.' This zone is found in many of the Departments of France, as Jura 

 and Doubs ; Milhau, Aveyron ; Lozere ; at St. Quentin and Verpilliere, Isere ; and in 

 the Sarthe and Calvados. 



'Family.— LYl^OCEKkHIDM— continued. 



Genus V — Phylloceras, Suess., 1865. 



Shell discoidal, highly involute, with delicate sculpture sometimes supporting con- 

 tractions or elevations, or having the shell covered with fine striae, which, describe graceful 

 curves inclined towards the aperture. Body-chamber short; aperture simple, with 

 lateral or aural processes, directed forwards ; suture-line highly tortuous, forming eight or 

 nine lobes on each side of the mesial line ; saddles bladder- 

 shaped, with well-rounded terminations ; body-chamber widely 

 expanded and fan-shaped, with undulating radii, as seen in 

 Phylloceras heteropJiyllmn, Sow. (fig. 194). 



Professor Neumayr distinguishes in the Dogger and Malm 

 four subgroups, of which the following are the types : — 1. 

 Phyll. heteropliyllum, Sow. ; 2. Phyll. tatricum, Pusch ; 3. 

 Phyll. capitanei, Catullo; 4. Phyll. ultramontanum, Zieten. 

 Fia. \^^.—iPhyiiQceras iietero- This gcuus first appears in the Trias, where we find Phyll. 



phvllumf Sow. , 



debile, Hauer, Phyll. despectum,M.o]s., Phyll. Neojurense, Quenst., 

 Phyll. occultum, Mojs., Phyll. pumilum, Mojs., Phyll. invalidum, Mojs. 



In the Middle Lias appear Phyll. Loscombi, Sow., Phyll. Buvignieri, d'Orb,, Phyll. 

 Zetes, d'Orbig. 



