264 CRIOCERAS. 



Genus STOLICZKAIA, Neumayr. 



Forms allied to ffoplites dutempleanu*. with expanded body- 

 chamber, embracing three-fourths? of a whorl. Margins of 

 aperture curved, produced at tin- middle of the flanks, slightly 

 eiii:irginate at the external side. Inner whorls with radial ribs 

 which are not interrupted on the external side, and usually here 

 attain their maximum strength; body-chamber smooth or with 

 thickened ribs; external side without keel or furrow. Lobular 

 line branched, consisting of a siphonal, two lateral, and one or 

 more less dependent sutural lobes. 



Eight species ; India. 



STOLICZKAIA DISPAR, Stol. T. 112, figs. 664, 665. 



Genus CRIOCERAS, Leveillg. 



A part of the evolute cretaceous Ammonites is connected with 

 Lytoceras, another with Olcostephanus ; for a third group, which 

 we will here embrace under the name of Crioceras, the direct con- 

 nection with Acanthoceras and especially with Ac. angulicosta- 

 tum, is shown by the investigations of Pictet and Quenstedt ; it 

 is these evolutes rolled up in one plane, in which, beside the 

 siphonal and the one-pointed antisiphonal lobe, there are on 

 either side two asymmetrically divided laterals and auxiliaries 

 present. Hen- also. acem-ding to the dim-rent curvature. <evernl 

 genera have been est ablished. upon the small value of which 

 Oiienstedt has expressed himself, and in tact the greatest capri- 

 cimisncss reigns in referring species to one or another of them : 

 Pictet had already referred all the forms belonging here, which 

 to his time had been embraced under Crioceras or Ancyloceras, 

 and Toxoceras also, cannot be separated from it ; for the whole 

 group of forms, the oldest name, Criocerax. must be retained. 



Ammonites diverging from Acanthoceras, rolled nj) in one 

 plane, the whorls of which are not or only partially in contact, 

 llesides the siphonal and the one-pointed ant isiphonal hbc. 



there are, on either side, but two latei-al lobes, asymmetrically 



divided into paired halves. 

 Sixty-two species. 



CRIOCERAS CRISTATUM, d'Orb. T. 100, fig. ;VJ-J. 



