158 Crick: A Rare Form of Acliuocamax (.1. Grossoiivrei). 



\= AcfiiiocaiiKix maniDiillaftis Nilsson, -v/). *], but it differs 

 from that species in having- the section of g^reatest diameter 

 lower than in A. subvoitricosiis, in being- more depressed, in 

 having- a shallower alveolus, in havingf the transverse section of 

 the alveolar end somewhat trapezoidal instead of subtriangular, 

 and in several other minor characters. 



M. Janet's larg^est specimen was found in the neig-Jibourhood 

 of Beauvais (Oise), France, in the Marsupite chalk ; the second, 

 a younger and more elong-ated form, was obtained from the 

 mag-nesian chalk at Margny-les-Compi6g-ne (Oise), France ; 

 whilst the third, a still young-er and more elong-ated form than 

 the second, was collected at Beauvais at the same horizon as 

 the larg-est specimen, tog-ether with Actinocamax vcrus and 

 Marsupites ornatiis. 



In the paper to which reference has already been made, M. 

 Janet t founded the species Actinocamax Toiicasi upon a sing-le 

 specimen, which differed from Actinocamax Grossoiivrei in being- 

 relatively much smaller at the alveolar end and much wider at 

 its most inflated part, but M. Grossouvre| has since pointed out 

 that yl. Grossouv re i and A. Toiicasi diXt. not distinct species, but 

 extreme forms of the same type connected by a series of inter- 

 mediate forms. 



In France, then, the species occurs in the Upper Santonian 

 and the Lower Campanian. |[ 



Actinocamax Grossoiivrei is a widely distributed species ; it 

 occurs in the north of France, in the north of Germany, and 

 in Scania, but everywhere it appears to be very rare. M. 

 Grossouvre,§ however, states that in the Pyrenean reg:ion, 

 judg-ing- from the numerous frag-ments which have been found, 

 it would appear to be relatively abundant. Wherever the 

 species is found it occurs on the same horizon as Actinocamax 

 granulatiis and Actinocamax venis. It is interesting- therefore 

 to note that in Yorkshire also it is associated with the saiiie two 

 species of Actinocamax. 



* I'ftrifical.'t Suc-caiui, 1S27, p. 10, pi. ii., tig-, z. .^ee also J. C". .Mobcrg-, 

 Cephalopocierna i .Sveriges Kritsystem, pt. 2 (Sverig-. Geol. L'lidorsok., 

 Afhandl., Ser. C, No. 73, 1885), p. 53, pi. v., fig-. 27 ; pi. vi., figs. 1-12. 



I Hull. See. gr«^ol. Fiance, s«^r. 3, vol. xix. , No. 9, .Nov., 1891, pp. 719, 720, 

 pi. xi%-., figs. 4rt, b, c, and text-fig^. i. 



:;; Bull. .Soc. g-«^ol. France, sir. 3, vol. xxvii., \o. j, June, iSgg, pj). 

 129, 130. 



Ji Ibid., p. 133. 



II See A. de (jrossouvie, ' RccheiTJies sur la craic supcM-icurc,' pi. i., 

 fasc. 2, 1 90 1, pp. 796-801. 



Naturalist, 



