IllllMV OB VERMU BR \N i'.i: INCH. 1 19 



One specimen in the Museum of Comparative Zoology baa somewhat deeper 

 channels than ia usual in tl tberwise quite similar to the i 



Quenstedt identifies this variety with 

 .1 n his "Ammoniten der Schwabischen Jura," but from 



this species it d atially, if we are right in our selection of the form to 



which the name Amm. krid&m, Oppel, has been applied. Undoubtedly then 

 dose resemblance between this Bpecies and n/um, on the one band, and Ar,i. 



a the other. The young and the channels separate it from the former, 

 ami ti ireadth of the whorls, channels, caloceran pike, and Butures, from 



tlit- latter. The raricostatus-like form of the whorl and pilae, and absence of 

 tubercles, distinguish it from what we consider to be the true kridion, Zieten's 

 cimen from Kalthenthal, near Stuttgardt, has exactly the aspect 

 of this ind though the abdomen looks somewhat broader in Zieten - 



tinn the pihe have no tubercles. It is more like this species than anj form of 

 if the Ggure is accurate. 



Caloccras laqucoides, llwrr. 



In this specimen, now in the collection of the Museum at Stuttgardt, found, 

 according to Fraaa, in the Angulatus bed, there is a most singular mingling 

 nt the I'll i tgueum with the peculiar pita * ► t ( /.' cklandi, 



\ 



I nd adult whorls are Bmaller and more numerous than those of 



. anil like those of lagueum. The abdomen, however, has narrow 

 channels, and many of the pilae in the adult have large tubercles somewhat 

 thrown back, which give them the aspect of the undivided pilae of - 



usually two or more of the linear | >:!:»■ of our vai • 

 i the tubercles when covered by the shell <1" not extend into spines, 

 • ■main mere tubercles. 

 In old age or on the last whorl of this specimen, which may perhaps be 

 lurely old, the intermediate pilse alone are found, the stunt tuberculated 

 simnrii'nsc-liki' pilae having become obsolescent At this time the form and 

 of the whorl an- precisely as in laquntm, except the channels; 

 remain very much shallower. Qpon the whole, therefore, it is prob- 

 able that this may 1»- a distil Together with others, it -how- that 

 « forms which are the morphological equivalents of the tuber- 

 culated, keeled, and channelled pi Vermiceras, Coron 

 and A 



