242 W. H. Hudleston — Fossil Shells from South Australia. 



wards into reflexed ribs. In the body-whorl (of the only available 

 specimen) these ribs become few in number and very broad, giving 

 a very characteristic appearance to the shell : they do not appear to 

 pass over the ventral (siphonal) area. The suture-lines are only 

 exposed over portions adjoining the siphonal area, but where exposed 

 are exceedingly distinct and well defined. There is a general 

 roundness in the crenulations of the entire suture-line, which, on 

 the whole, may be said to tend towards simplicity. The upper lateral 

 saddle is not deeply cleft, whilst the upper lateral lobe is tridigitate, 

 and almost on a level with the siphonal lobe. 



The specimen is well preserved in a hard black argillo-calcareous 

 nodule, which contains Nucula, Cardiim, Pinna, Serpulites, etc., and 

 the shell, which is highly nacreous, shows good iridescence. It was 

 found at Primrose Springs, north of Lake Eyre, and is stated to be 

 the first Ammonite discovered in South Australia. 



This extremely compressed and carinated species, so far as 

 external appearances guide us, has some resemblance to the Murclii- 

 sonce and concavus-growp of Ammonites now referred to Ludicigia 

 and Lioceras. The umbilicus in its step-like character strongly 

 reminds us of the latter. On ascending higher in the geological scale, 

 we are again reminded of such forms as Am. JZenrici, d'Orb., and 

 Am. canaliculatus, Miinst. The Cretaceous species, so far as my 

 experience goes, do not offer so many points of resemblance to the 

 South Australian form. 



It is worthy of remark that Ammonites have hitherto proved 

 scarce in the Mesozoic deposits of Australia. Tenison Woods, 

 writing in the year 1882 (T.R.S. N.S. Wales, vol. xvi. p. 150), 

 remarks that only seven species had been recorded including the forms 

 recognized by Moore. He described a new form under the name 

 of Am. olene, which was said to resemble Am. biflexuosus, d'Orb., of 

 the Great Oolite. Mr. R. Etheridge, jun., has figured five species of 

 Ammonites in his "Queensland Palasontology " (unpublished). 



Alaria or Anchura, sp. Plate IX. Fig. 2. 



Anchura (Conrad) is a sub-genus of Alaria (uionodactyl), 

 where the wing presents a securiform bifurcation at the extremity. 

 It seems confined to the Cretaceous, e.g. Anchura carinata, Mantell 

 (Fischer, Man. Conch, p. 676). 



Approximate length, without the " tail " 35 ram. 



Spiral angle 23°. 



The number of whorls is from ten to twelve ; these are full and 

 rounded in the early stages (the extreme apical whorls are unknown), 

 carinated in the later stages ; carina nearly median, and ornamented 

 with short thick tuberculations ; a second carina is sometimes dis- 

 played at the base of the whorls. Body-whorl angular, salient and 

 bicarinated ; the posterior carina very strong and prolonged into 

 a stout digitation, the true termination of which is unknown. In 

 some specimens the carinas of the body-whorl are tuberculated, in 

 others apparently not so. The sutures are rather open, so that the 

 base of the whorls are partly uncovered. Other indications wanting. 



