388 O. C. Crick — Jurassic Cephalopoda — 



cover the entire surface of the test as in the Australian species, but 

 are confined to the peripheral and umbilical regions. The present 

 species is closely allied to Nautilus ornatus, Foord and G. C Crick/ 

 from the Inferior Oolite of Sherborne and Dundry, but it is at once 

 distinguished by the character of its ornaments. From Nautilus 

 intermedius, J. Sowerby," and N. striatus, J. Sowerby,^ the Australian 

 form is distinguished by the ornamentation of the shell ; it is also 

 less inflated than N. striatus. The sculpture of the present species 

 bears a marked resemblance to Dumortier's figures * of the test of 

 Nautilus nf^osiis, Buvignier ^ ; but the Australian shell lacks the 

 transverse lines, which Buvignier notes in the young of his species, 

 and which Dumortier figures on a specimen 140 mm. in diameter. 

 N. rugosiis is, moreover, a much more compressed shell. According 

 to Dumortier it is not very rare in the zone of Ammonites armatus. 

 Nautilus Jourdani, Dumortier,'' from the Upper Lias of England and 

 France, differs from the Australian species by its sculpture and the 

 angular margin of its umbilicus. 



Locality.— Champion Bay, Western Australia. 



AMMONOIBEA. 



Ammonites (Doesetensia, S. S. Buckman). 



Ammonites [Dorsetensia) Clarlnei, sp. nov. (PL XII. Figs. 2a, b, c.) 



? 1870. Ammonites radians, C. Moore, "Australian Mesozoic Geology and 

 Palaeontology, " Quart. Journ. Geol. Soc. vol. xxvi. pp. 230 and 232, 

 pi. XV. fig. 2. 



Sp. char. — Shell discoidal, compressed, evolute; greatest thickness at about the 

 middle of the lateral area, nearly three-fourths of the height (breadth) of the whorl. 

 Number of whorls unknown ; inclusion small ; umbilicus large, open, shallow. 

 Whorl subquadrate in section, higher than wide, very slightly indented by the 

 preceding whorl. Periphery sloping on either side from a small well-marked solid 

 carina ; in the cast the peripheral area is flattened, having a depressed band or 

 rudimentary sulcus on each side of the carina ; the inner whorls have a flattened 

 peripheral area with a clearly marked sulcus on either side of the carina. Sides 

 feebly convex ; inner area imperfectly defined, slightly convex, sloping towards the 

 umbilicus. Chambers moderately deep, in depth at the periphery nearly two-thirds 

 of the height (breadth) of the whorl. Suture-line not very complicated ; peripheral 

 (siphonal) lobe narrow, fairly deep, with nearly parallel sides, divided by a rather 

 low median saddle ; first (superior) lateral lobe somewhat deeper than the peripheral 

 (siphonal), trifid; second (inferior) lateral lobe small, trifid, scarcely one-half the 

 size of the first lateral ; a small auxiliary lobe ; external (siphonal) saddle broad, 

 divided by a small secondary lobe into two unequal parts, the smaller of which is 

 towards the peripheral (siphonal) lobe ; lateral saddle much smaller than the external 



1 Ann. Mag. Nat. Hist. [6], vol. v. p. 273, fig. 7. When the specimen here 

 represented was figured the locality was not known, but Mr. Etheridge, F.R.S., 

 in whose collection the specimen was originally, tells the writer that the "D" 

 written in ink upon the specimen means " Dundry." 



' Min. Con. vol. ii. p. 53, pi. cxxv. 1816. 



3 Ibid. p. 183, pi. clxxxii. 1817. 



* Etudes paleontologiques sur les depots jurassiques du Bassin du Rhone, pt. 3, 

 p. 54, pi. viii. ff. 3, 4 ; t. 3 especially. 



^ Statistique geologique, miner alogique, minerallurgique, et paleontologique du 

 Department de la Mouse, 1852, Atlas, p. 46, pi. xxxi. ff. 23-25. 



^ Etudes paleontologiques sur les depots jurassiques du Bassin du Ehone, pt. 4, 

 p. 44, pi. vii. ff. 1-5. 



