Vol. 69.] JURASSIC AMMONITES FROM JEBEL ZAGHUAN. 555 



These dimensions agree with Fucini's variety (only the umbilicus 

 is 40 instead of 42 per cent.) and also with his ' Grammoceras ' 

 portisi. But the latter has a sulcicarinate, fairly broad venter and 

 more rounded sides, whereas in the former the sulci are faint and 

 the sides flatter ; and these characters, together with the sharper 

 umbilical border, bring it near the present variety. 



The ornament consists of flexiradii which are somewhat less 

 angular than those of the group described previously, but would 

 still be classed as subanguliradiate. Some of the ribs are united on 

 the inner half of the side, and come out more prominently then, as 

 illustrated in Fucini's fig. 8 a of pi. viii. The costation of the 

 inner whorls also seems to agree very well with that given by 

 jFucini. 



Of the other forms cited above, the var. zittelianum has an 

 umbilicus of 38 per cent, only : in other words, it is smaller than 

 that of my specimen by the same amount as that by which the 

 type portisi exceeds it. The costation is too coarse and distant, 

 however; whereas, on the other hand, in the var. contrarium it 

 is too fine, and here the umbilicus is but 33 per cent, of the 

 diameter. 



Protogrammoceras (?), sp. nov. 



Of this form only a small fragment preserved in grey limestone 

 is in my collection ; and, if the specimen had not been found in 

 company with fossils of undoubted Mesoliassic age, I probably 

 should not have hesitated to identify it with Harpoceras hicarinatum 

 (Ziet.) =cumulatum Hyatt, considering the distinctive characters 

 of this form. But, as I pointed out in the first part of this paper 

 (p. 542), despite this apparently close resemblance, due in part, 

 undoubtedly, to the peculiar mode of its preservation, I am inclined 

 to question its affinity to Zieten's form, especially as the umbilicus 

 and the suture-line are unknown. 



The specimen shows close agreement with an undoubted IT. hi- 

 carinatum (Ziet.) from Milhau (Aveyron) in my collection, and 

 also with the figures given by P. Iteynes 1 and E. Dumortier." 

 Wright's form 3 seems to be less closely costate, but agrees well in 

 its thin and flat section : it is named H. hicarinatum (Miinster) ; but, 

 as Prof. Haug has pointed out, Mlinster's hicarinatus is an Arcestes. 

 Hyatt's new specific name for Zieten's Ammonites hicarinatus is, 

 therefore, superfluous. 



Zieten's figure has more rounded sides and a smaller umbilicus 4 

 than that given by Wright ; also the radial line is less falcate. 

 But there seems to be a good deal of variation in this group (the 



1 ' Monographic des Ammonites du Lias Super.' pi. v, figs. 18-30. 



2 ' Depots Jurass. du Bassin du Ehone : pt. 4 — Lias Sup.' pi. xi, figs. 3-7 & 

 p. 55. 



3 'Lias Ammonites' Monogr. Pal. Soc. (1878-86) p. 462 & pi. lxxxii, 

 figs. 9-10. 



1 C. H. von Zieten, ' Verstein. Wiirttembergs ' 1830, pi. xr, fig. 9. 



