THE INFERIOR OOLITE OF DORSET. 



605 



Harpoceras dispansum (Lycett). 



My authority for this name is a specimen sent by Dr. Lycett, 

 labelled " Am. dispansus, Lye, Frocester Hill." 



I have one specimen from near Crewkerne which agrees very well 

 with it. 



Harpoceras Moorei (Lycett). 



Ammonites Moorei, Lyc. Cotteswold Hills, pi. 1. fig. 2. 

 A. Moorei (Lyc), J. Buckman, Quart. Journ. Geol. Soc. vol. xxxvii. 

 p. 65, fig. 7. 



Localities. Found in layers of comminuted shells in the sands at 

 Bradford Abbas, Yeovil Junction, &c. : not very common. 



Termination. A slight double curve produced on the ventral area. 



Harpoceras cornu, S. S. Buckman, n. sp. 



Ammonites subradiatus, J. Buckman (non Sowerby), "Terminations 

 of Ammonites," Quart. Journ. Geol. Soc. vol. xxxvii. p. 61, fig. 2. 



This species is compressed, with strongly marked ribs, which are 

 slightly reflexed and not so prominent close to the termination. 

 They seldom bifurcate ; but now and then a rib comes in between 

 which is not continued all across. 



Keel distinct, with very sloping sides. 



Aperture sagittate. 



The umbilicus varies somewhat in width ; it is, however, rather 

 wide, with strongly marked ribs, showing also a certain portion of 

 each whorl. 



Shoulder concave. 



Termination. Like that of Harpoceras concavum (Sow.); but it has 

 a very long horn on each side. 



Difference. This species resembles Harp, concavum, but is distinct 

 on account of the horn which the termination possesses, and which I 

 I have never seen in that species. The ribs are also far more 

 marked, and the umbilicus is far wider. 



This species never attains the same size as H. concavum ; but very 

 small specimens of these two species are hard to separate. 



This species might possibly be mistaken for the young of Harpo- 

 ceras Murchisonai (Sow.) ; it, however, never attains the size of 

 H. Murchisonce, is found at a higher level, has a more prominent 

 keel, is far thinner towards the keel, is more acute, and its ribs are 

 less prominent and rather more rounded. 



Dimensions. Diameter 2'50 inches, umbilicus 0*60, breadth of 

 aperture 0*48, outer whorl from back to front 1*15. Another spe- 

 cimen measured — diameter 2'70 inches, umbilicus 0*82, breadth of 

 aperture 0*50, outer whorl from back to front 1*06, length of 

 horns 0*65. 



I have never seen a specimen of this species which exceeded the 

 diameter of about 2| inches. 



Compare these measurements with those of a medium-sized Harp, 

 Murchisonoe (Sow.). 



