THE INFERIOR OOLITE OF DORSET. 



599 



Spbueroceras Wrightii, S. S. Buckman, n. sp. 



1849. Ammonites microstoma, Quenstedt (non d'Orbigny), Cepha- 

 lopoda, tab. 15. fig. 6. 



Localities. Humphriesianum zone, Oborne, and near Sherborne : 

 common. 



This species was figured by Quenstedt under the name of A. mi- 

 crostoma ; but it does not at all agree with the figure of A. micro- 

 stoma given by d'Orbigny (who named it) in ' Terr. Jurassiques.' 



Dimensions. Diameter, adult, 1'59 inch; umbilicus 0*55 inch; 

 umbilicus, omitting the last chamber, 0*22 inch ; breadth, same 

 place, 0*85 inch ; breadth across termination 079 inch ; termina- 

 tion, from back to front, 0*50 inch. 



Length of body-chamber very nearly one whole whorl. 



Named in compliment to Dr. Wright, of Cheltenham, who is so 

 ably working at the Lias Ammonites. 



CoSMOCERAS PaRKINSONI (Sow.). 



1821. Ammonites ParHnsoni, Sow. Min. Conch, pi. 307. 

 1845. A. ParHnsoni (Sow.), d'Orb. Ter. Jurass. pi. 122, variety. 

 1849. A. ParHnsoni gigas, Quenstedt, Ceph. tab. ii. fig. 1 (adult 

 form). 



1854. A. ParHnsoni (Sow.), Morris, Catalogue, p. 294. 



1856. A. neuffensis, Oppel, Juraformation, p. 378, no. 48. 



1856. A. ParHnsoni (Sow.), Oppel, Juraformation. 



1849. A. ParHnsoni dejoressus, Quenstedt, Ceph. tab. ii. fig. 5. 



1878. ParHnsonia Parhinsoni (Sow.), variety, Bayle, Exp. de la 

 Carte geol. de la France, vol. iv. pi. 67. figs. 2, 3. 



1878. ParHnsonia neuffensis, Bayle ?, pi. 67. fig. 1. 



This species is somewhat variable, and has been much misunder- 

 stood. The figures given by d'Orbigny (' Terr. Jurass.' pi. 122. figs. 1 

 & 2) are evidently of a variety of Sowerby's species. This same 

 variety is again figured by Quenstedt under the name of A. Par- 

 Hnsoni d&pressus ; and as such it was quoted by Oppel (' Juraforma- 

 tion ') as a synonym for ParHnsoni. It was also figured by Bayle 

 under the name of ParHnsonia ParHnsoni (see synonyms). 



This variety differs from Sowerby's type in having far fewer ribs, far 

 less inclusion (consequently the whorls are not so broad from front 

 to back), and in possessing rather marked tubercles. 



To this variety I give the name of Cosmoceras ParHnsoni, var. 

 rarecostatum, S. S. Buckman. 



The fragment figured by Quenstedt (Ceph. tab. ii. fig. 1) under 

 the name of Ammonites ParHnsoni gig as is merely the very adult 

 form of the true ParHnsoni ; and this adult form occurs at Half-way 

 House of very large size, one specimen measuring 19 inches across, 

 and yet lacking a large portion of the outer chamber. This adult 

 form was named by Oppel Ammonites neuffensis, he giving Quen- 

 stedt's figure as a reference. Bayle has also figured a specimen as 

 Am. neuffensis ; but I consider that his figure most probably repre- 

 sents merely a rather fine-ribbed variety of a medium-sized trua 

 C. ParHnsoni. 



