72 POMPECKJ. JURASSIC FAUNA OF CAPE FLORA. [NORW. POL. EXP. 



The chief lobes and saddles in particular agree very well with those of 

 the species described from the Ishma in Northern Russia. The drawing, how- 

 ever, which Count Keyserling gives of the lobes of his Amm. Ishmae (I c. PI. 

 22 fig. 15) shows a very different character. I was nevertheless able to con- 

 vince myself that the drawing in question is inaccurate. A splendidly pre- 

 served specimen of Macrocephalites Ishmae from Petschora Land, that I ex- 

 amined, shows a lobe-line, which, up to the second lateral lobe, agrees per- 

 fectly with the above drawing of the lobe-line of Macrocephalites Kcettlitsi 

 n. sp. (On this piece also, the auxiliary lobes are distinct.) The species 

 in question differs from Macrocephalites Ishmae: 



1. In the form of the whorls. In Macrocephalites Ishmae, the height 

 of the whorls is greater than their width, the whorls are more slender, and 

 that to at a size corresponding to that of the specimen of Macrocephalites 

 Kcettlitsi before us. 



2. In the sculpturing. Even in large specimens Macrocephalites Ishmae 

 is coarsely ribbed. The specimen examined by me still showed quite 

 distinct ribs up to a diameter of 105 mm., while Macrocephalites Kcettlitzi 

 loses the ribs as early as at 50 mm. 



From Windy Gully, north-east of Elmwood, Cape Flora, Newton described 1 

 several ammonites as varieties of Amm. (Macrocephalites) Ishmae Keys. 

 Of these ammonites the "smooth variety" might agree with the species before 

 us ; (1. c.) the outer whorl of a small specimen is stated to be "nearly smooth". 

 The drawing of this form (1. c. PI. XL. fig. 3) shows another section than 

 our fig. 12b on PI. II, but we must not forget, that the drawing given by 

 Newton contains no accurate profile of the whorls. The inner whorls in 

 this specimen are not bisected in the plane of the greatest diameter. 



Newton's fig. 1 shows a coarse sculpturing at a diameter of about 70 mm.; 

 and not until then does the whorl begin to become smooth; but whether the 

 smoothness of the whorl beginning there is due to weathering of the piece in 

 question, or whether it corresponds with an actual disappearance of the 

 sculpturing, Newton does not say. At any rate, fig. 1 of Newton's Amm. 

 (Macrocephalites) Ishmae Keys. var. arcticus is more closely allied to the 



1 E. T. Newton and J. J. H. Teall, 1. c. p. 500. pi. XL. 



