24 INFERIOR OOLITE AMMONITES. 



Tlie position of Lioceras bradfordense is somewhat peculiar, it being the 

 one species of Lioceras which approaches in some things nearest to Ludwigia. 

 Though occurring in the Murchisona3-zone, or midway as it were between Lioceras 

 opalinum in the zone of that name, and Li. concavum in the Sowerbyi-zone, it is 

 not the connecting link, as one would expect, between Li. opalinum and Li. con- 

 cavum. Bigger than either, with larger umbilicus, it has not quite the true 

 Lioceras form.. Nor again, is this species, in spite of the resemblances I have 

 pointed out, any intermediate form between Lud. Murchisonce. and Li. concavum. 

 The latter species is not derived through Li. bradfordense from Lud. Murchisonce as 

 I have heard it stated, but is clearly a descendant of Li. opalinum. When I first 

 applied the name bradfordense I was uncertain if Quenstedt's Am. Murchisonce 

 acutus was the same. Still, the name acutus having been used for an Ammonite 

 by Sowerby and again by Tate for a Harpoceras, I could not have retained it in any 

 case. Having then, in 1881, more or less established the name bradfordense I do 

 not think it at all advisable to alter it, although it is now in the genus Lioceras. 



On Plate IV, figs. 5, 6, is shown a medium-sized specimen of this species 

 with the termination. At this size the species may be said to be in all respects 

 of the true Lioceras form, and, with its broad flat sides and small deep 

 centre, could not, I think, be easily confounded with any specimen of L. Mur- 

 chisonce. In fact, I have generally found it more difficult to distinguish poorly- 

 preserved specimens of this size from Li. concavum. Fig. 7 gives the side view of a 

 younger and smaller shell. Its front view is proportionately much the same as Fig. 6. 

 Fig. 8 shows two suture lines taken from the large specimen figured on Plate V 

 and placed here for convenience. Plate V, figs. 1, 2, show a larger, but hardly 

 full-grown example, with the body-chamber, occupying just half a whorl, present. 

 (The specimen has just an indication of termination.) Fig. 1 shows the receding 

 of the inner margin mentioned before, which in this species varies in amount 

 with the age. Fig. 2 shows the small amount of keel present even where the test 

 is on, and the almost rounded character of the ventral area on the body-chamber. 



