MBEKOCERATIDAE Waagen. 



LECANITINAE Hyatt 



Paralecanites Diener 



The subgenus Paralecanites was established by Diener^ for am- 

 monites similar to Lecanites Mojs. but distinct from it by the absence 

 of the second lateral lobe. To Paralecanites belong very evolute forms 

 with low and little embracing whorls, wide umbilicus, practically no 

 sculpture and simple septa consisting of a siphonal lobe, one external, 

 one lateral and the beginning of an auxiliary saddle. 



Frech^ proposed to unite Paralecanites with Paraceltites Gemm. but 

 Diener,^ in a later article, showed that there was a fundamental dif- 

 ference between the two genera in so far as Paraceltites has an undi- 

 vided siphonal lobe and always shows a rather strong sculpture. 



Hyatt and J. P. Smith* accept Paralecanites as an independent 

 genus and refer to it a form found in the Meekoceras beds of the Lower 

 Triassic, Paralecanites Arnoldi Hyatt a. Smith.^ This species is in 

 so far interesting as it shows apparently one lobe more than the type 

 species Paralecanites sextensis Dien. The authors explain that this 

 lobe .is not an auxiliary, one, but an internal lobe which becomes visible 

 outside of the umbilical seam on account of the evolution of the shell. 

 It is to be supposed that the internal lobes of the genus "would consist 

 of an antisiphonal lobe flanked by an internal lateral as this is the 

 case with all primitive ammonites of this group." In the case of P 

 Arnoldi, the authors actually observed that there exists a divided anti- 

 siphonal lobe and that the next lobe, the internal lateral, appears be- 

 yond the umbilical seam. 



In the region of Altuda Mountains, Dr. J. A. Udden has found a 

 very evolute cephalopod which shows a peculiar suture, very similar 

 to that of Paralecanites Arnoldi. This cephalopod is so evolute that 

 the dorsal portion touched and excavated by the next smaller whorl is 



'Diener, Amm. u. Orthoc. d. Siidtirol. Bellerophonkalk, p. 66. 



''Freeh, Lethaea Palaeozoica, 2 Bd, 3 Lief, p. 552. 



'Diener, Ueb. d. syst. Stall, d. Amm. d. Siidalp. Bellerophonkalkes, p. 426, et seq. 



•Hyatt and Smith, Triass. ceph. genera of America, p. 136. 



'Hyatt and Smith, loc. cit., p. 136, pi. 64, fig. 1-16; pi. 77, fig. 9-12. 



