486 NEW YORK STATE MUSEUM 



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however shown the correctness of the identification. Hyatt asserts 

 that this form is sometimes quite irregular in its mode of coihng and 

 one of our specimens appears to indicate something of the same kind. 



Hyatt made the following observation in regard to this irregu- 

 larity of the mode of coiling: 



In several specimens of Jason the first whorls may touch, the 

 ephebic volution may be open and free and yet the extremity of the 

 living chamber again come in contact. 



In regard to the earliest whorl it is stated by Hyatt that the " um- 

 bilical perforation is large and the impressed zone is absent until 

 the whorls come in contact " and that it is invariably absent in 

 gerontic whorls. Our text figure 44 gives a section of the earliest 

 whorls of a specimen from Valcour. This shows the large um- 

 bilicus, rapid growth of the first whorl, absence of costae on the 

 latter and their beginning on the second. 



Suborder E. CYRTOCHOANIXES Hyatt 



Division I. ANNULOSIPHONATA 



Family loxocefj^tidae 



Genus loxoceras McCoy 



This genus was originally described by Hyatt as Sactoceras [1884, 

 p. 273] and based upon Orthoceras richteri Barrande as 

 type. Later on [1900, p. 527] McCoy's term Loxoceras, which 

 had been proposed in 1844 for Carboniferous forms but not 

 recognized, was adopted. 



The diagnostic characters of the genus are to be seen, in the ortho- 

 ceraconic or cyrtoceraconic, more or less longicone form, the highly 

 nummuloidal segments of the siphuncle in later stages and its posi- 

 tion in the center or near the center of the phragmocone ; and in the 

 still irregular character of the endosiphuncular deposits in distinc- 

 tion from those of the Actinoceratidae. Thus defined the genus is 

 said to range from the Lower Siluric into the Carboniferous. The 

 reference of the genus to the Cyrtochoanites demands that the septal 

 necks shall be " as a rule bent outward and crumpled, and generally 

 short " and its being placed under the Annulosiphonata requires 

 that the endosiphuncular deposits " when present are always 

 gathered about or encrusting the septal necks." 



The faunas here described contain only one species of which it 

 could be asserted that it belongs here. This form ( L . m o n i li - 

 forme) is clearly in all its characters a close relative of O . 

 richteri, the genotype, though of smaller size, and with a little 

 more excentric position of the siphuncle. 



