﻿150 



MR. S. 



BUCKMAN OjST CERTAIN 



[Feb. 1905, 



Am. Eudesianns, d'Orbigny (op. cit. 1846, p. 386 & pi. cxxviii) ; 



niortensis hem era. 

 Am. Adeloides, Kudernatsch, ' Die Ammoniten von Swinitza ' 



Abhandl. d. k.-k. Geol. Reichsanst. vol. i (1851) Abh. 2, 



p. 9 & pi. ii, figs, 14-16. 



Genus Megalytoceras, 1 nov. 

 Genotype, Lytoceras confusum, S. Buckman. 



Definition. — A genus which has much the aspect of the 

 jurense-grou-p* smoothness being very noticeable ; but it possesses 

 an ornate suture-line, with narrow-stemmed, highly-developed 

 lobes (see fig. 1) like Lytoceras, or Thysanoceras. Like Lytoceras 

 it shows plain periodic ' flares,' but they are not associated with 

 sculpturing, in the species at present known, and they are confined 

 to the young stage. The development of a broadly- deltoid cross- 

 section of whorl, and the fact that in the smooth stage the whorls 

 are still evolute, are also important features. 



Fig. 1. — Suture-line of Megalytoceras confusum (S. Buchnan) 

 from the type-specimen, obtained by the removal of the 

 test ; some of the finer details may have suffered in the 

 process. (Natural size.) 



Megalytoceras confusum (S. Buckman). (Fig. 1, & fig. 9, p. 152.) 



1881. Lytoceras confusum, S. Buckm. ' Amm, Inf. Ool. of Dorset ' Quart. Journ. 



Geol. Soc. vol. xxxvii, p. 601 (description). 

 [1883] L. confusum, S. Buckm. Proc. Dorset Nat, Hist. Field-Club, vol. iv, 



pi. iii, tig. 1 & p. 143 (fig. & descr.). 



Remarks. — I give these references, because on the Continent 

 the fact that this species is figured has been overlooked; and it 

 has been confounded with others of more recent date. A tracing 

 of the suture-line of the holotype is appended (fig. 1, above). 



1 Meyas, large ; fteya-, for jueyaXo- : the Greeks themselves warrant this; 

 and it is very desirable in the present case. 



2 The genotype obtained its name, because it bad been mistaken for 

 P. Jurense, and had thereby caused confusion in stratal correlation. 



