FIFTH, OB \ ., H -11 



Asterocoras impendens. n 

 iit, l.ia.i Ami 



Amm impt 



S 



Thi- E a the gn ater amounl of the involution, the 



smaller >!/.'•. the earlier age at which the same form of whorl i< passed through, 

 and the earlier age at which degeneration begins. 



In Wright's "lias Ammonites" the 6gures of /.' 



show in t!.' manner whal are the proper limits of the species. The fig- 



e VI. I J.4. i- taken from the less involute form, which 



retains it- pita until a late Btage of growth; that of Colienotx on Plate XXII 1> 



is an old and very large individual of impendent, which approximate - to B h, but 



■ usual difference in the amount of involution and begins to Bhow i 

 eration of the | earlier than is common in Brooki; that ol ( 



XXI 1 A 1 I - - yet more accelerated form, growing old and losing 



irlier than' in the specimen shown on Plate XXII. B The figure of 



- -■ ted than the specimen figured on Plate 



XXII A. ! ad has al-<> somewhat Btouter whorls. The young li 



on Plate XXII. A. Fig. 1. is Bimilar to the adult of the true l /.' . having 



the same form, pile, and involution until a late nealog 



All <>f these forms have the broad abdomen, the peculiar channels, and the 



Ice /•' . and are quite distinct from the true A < They are 



undoubtedly transitional forms connecting the two species. Those who wish may 



join them, but, as we have previously said, all the series and about all the species 



of the i losely connected by intermediate forms and modifications, 



and. to l>e reall at, we must then also include the entire family under 



name. We doubt if any paleontologist would 



ort if he attempted to d<> thi<. 



Asterocoras denotatum, n 



A mm 



A mm 



aiveraallj placed either with / 

 •u either of th< It one com| figure 



■ 

 X X 1 1 A 

 Amrn it « dl be seen that 



' i 



and lh 



