part 3] AMMONITES FROM NEW ZEALAND. 295 



a quarter of the natural size) had its body-chamber accidentally 

 displaced ; but its normal diameter probably was not less than 

 300 mm. In the figure a break is shown at b, and the line of 

 displacement at d. There are seven constrictions and about eight 

 intervening ribs on the peripheral portion of the whorl, as in 

 Pliylloceras passati Bcehm, 1 with which species the example had 

 been identified by Dr. Trechmann. This costation does not seem 

 to be yet developed at a size corresponding with that of the Wai 

 Gralo form, appearing in the specimen here described at a diameter 

 of about 250 mm. Furthermore, the constrictions have a different 

 course in the JSTew Zealand form. The outer half, in side-view, 

 forms a very pronounced semicircular curve, and there is a very 

 distinct sinus forward on the periphery, reminiscent of Sowerby- 

 ceras or Schlueteria. This sinus is more prominent than that 

 shown in Neumayr's type of Pliylloceras mediterraneum? from 

 the Alpine macroceplialus beds (with a similar number of con- 

 strictions but less lateral angularity), or by Hang's 3 Bajocian 

 example, with nine constrictions. 



Pliylloceras mediterraneum. race indica Lemoine 4 does not show 

 this type of constriction, nor do the Argovian examples recorded 

 by me 5 from Tunisia. These have only five constrictions ; but it 

 is to be noted that, at a diameter corresponding with that of the 

 Trept specimens, 6 the form here described also has only five con- 

 strictions, although in this case the forward sinus on the periphery 

 is even more conspicuous. In order to obtain these inner whorls, 

 a worn example from the same locality as the large figured spe- 

 cimen was broken up, revealing the distinctness of the species. 

 Whether Pliylloceras Icawliiee Marshall 7 or Pliylloceras sp. m 

 Bcehm 8 are identical with the form here described it is impossible 

 to state. 



The suture-line is well-preserved, especially on the smaller 

 specimen, and agrees in general outline with that of Pliylloceras 

 mediterraneum as figured by Canavari. 9 Of the four larger leaflets 



1 'Die Siidkiisten der Sula-Inseln Taliabu & Mangoli ' Paheontographica, 

 Suppl. iv, pt. 3: ' Oxfordien des Wai Galo' (1907) p. 82 & pis. xv, xvi, 

 xvii. 



2 ' Jurastudien : III. Phylloceraten des Dogger & Malm ' Jahrb. K.K. Geol. 

 Keichsanst. vol. xxi (1871) p. 340 & pi. xvii, figs. 2-5. 



:i ' Note snr le Peristome du Pliylloceras mediterraneum ' Bull. Soc. Geol. 

 France, ser. 3, vol. xviii (1890) p. 328 & pi. iv. 



4 ' Paleontologie de Madagascar: pt. 8 — Ammonites d'Analalava ' Ann. 

 Pal. vol. v (1910) p. 3 & pi. i, fig. 1. 



3 'Jurassic Ammonites from Jebel Zaghuan ' Q. J. G. S. vol. lxix (1913) 

 p. 561. 



fi A. de Biaz, ' Description des Ammonites des Couches a Peltoceras trans- 

 versarium de Trept (Isere) ' 1898, p. 40 & pi. xvi, figs. 9-10, 



7 ' Some New Zealand Fossil Cephalopods ' Trans. N.Z. Inst. vol. xli (1908) 

 p. 144 & pi. xivrt, fig. 2673, right-hand fig. 



s ' Grenzschichten zwischen Jura & Kreide von Kawhia ' Neues Jahrb. 

 vol. i (1911) p. 17. 



'•' ' La Fauna degli Strati con Asjndoceras acanthicum di Monte Serra ' Pal 

 Ital. vol. ii (1896) text-fig. 6 on p. 39. 



q. J.G. S. No. 315, r 



