18 TYPE AMMONITES— VII 



Numbers of PLATES and SPECIES compared. 



More than one species to a plate (see Note i) 

 More than one species to a Number (see Note i) 

 One plate to a species (see Note 2) 

 Two plates to a species (see Note 3) 

 Three plates to a species (see Note 4) 

 Four plates to a species (see Note 5) 

 Five plates to a species (see Note 6) 



Add plates replaced 



1,051 



Notes on Notational Anomalies. 



Note i. — Plate 53 figures 3 species ; PI. ma is one species, 

 in b and c are another ; 116a, 116b, 116c, 118a, 118b, 121a, 121b 

 each figures a distinct species. In all these cases the numerical unit 

 was the original broadly conceived species of Simpson, syntypes of which 

 were separated and new-named. (In three other cases, however, PI. 42, 

 91 and 104, subordinate types of Simpson were raised to separate specific 

 rank, but independently numbered.) Result: Excess of species over 

 plate-numbers, 7. 



Note 2. — The 596 single plates representing a species all bear 

 simple numbers, with one exception (143a), in which case it may be 

 presumed that there was an original intention of adding a second plate. 



Note 3. — Of the 150 species represented by two plates each, in 

 120 cases the plates bear the letters A and B ; in 24 cases one is 

 unlettered, the other lettered A ; the remainder are anomalous : 138 A 

 and 138c (138B having been transferred to another species) ; 308 and 

 308B (no 308A) ; in two cases (396, 602) both plates bear the unlettered 

 number without distinction. Lastly, there are two cases where the same 

 species has plates of different numbers — Echioceras aureolum, 28 and 96 ; 

 Hildaites serpentiniformis, 138b and 267b. In the latter case it may be 

 presumed that 138b should have been re-issued or re-numbered 267a : 

 this case does not affect the totals. The previous case results in an 

 excess of one of plate-numbers over species to set against the opposite 

 excess explained in Note 1, leaving the final balance of six. 



Note 4. — Of the 27 species represented by three plates each, in 

 21 cases these are lettered A, B, C, the remaining six having an unlettered 

 plate, A and B. In two cases (354, 580) the unlettered plate was issued 

 after the others, and should more consistently have been lettered C 

 (this was recognized in the Corrigenda of Vol. VI, but in the case of 354 

 the instruction was to add A to the plate-number, instead of C, as was 

 correctly indicated for 580). 



Note 5. — In one case (590) one plate is unlettered, the others bear 

 A, B and C ; in the other nine cases all are lettered A, B, C and D. 



Note 6. — The five plates are lettered A, B, C, D and E (139). 



