418 THE LIAS AMMONITES. 



fimhriatam, but it is distinguislied from that and other coDgeneric 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. fimhriatum and Lyt. cornucopia; it is evidently a well-marked species of the 

 group to which it belongs. 



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

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

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

 opalinum, Turbo capitaneus, Gervillia lata, Rliynclionella cynocephala. This bed forms a 

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



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

 many ; the type specimen of Lyt. 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 Erance, as Jura 

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

 the Sarthe and Calvados. 



Family.— lATOC^^kHlD^—contijiued. 



Genus V — Phylloceras, Suess., 1S65. 



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 

 PItylloceras lieteropliyllum. Sow. (fig. 194). 



Professor Neumayr distinguishes in the Dogger and Malm 



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



V^ j ^^ / Phyll. heterophyllum , Sow.; 2. Phjll. tatricum, Pusch; 3. 



'^^<f^4MM^ Pfiyll' capiianei, Catullo ; 4. Phyll. ultramontanum, Zieten. 



Fig. \9)4,.—myiioceras hetero- This ffenus first appears in the Trias, where we find Phyll. 



pJiyllum, Sow. . 



debile, Hauer, P/iyll. despectum, Mojs., Phyll. Neojurense, QMeust, 

 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. 



