456 MB. s. s. btjck:3ia2«^ on the geoijping of some [Aug. 1898^ 



Genus Emileia,^ S. Buckm. 

 [Type : Emileia Brocclii (Sow.).] 



A Sphaeroceratoid ammonite-series distinguished from, the true 

 SjjJiceroceras by (1) very complicated septa ; (2) obtuse-ended 

 primary costae, in the form of elongate knobs ; (3) the loss in 

 phylogenedc development of the spheroidal form and the assumption 

 of a more discoidal or rotiform shape — as, for example, in Emileia 

 ^olymera (Waagen). 



The developmental feature noticed under (3) is the result of the 

 earlier inheritance of the ' excentric ' mode of coiling. Lateral 

 compression of the whorl proceeds in company with a decreasing 

 degree of envelopment. 



Genus (EcoPTTcurcrs, Neumayr. 



I have noted in the genealogical Table (II, facing p. 451) a Scaphi- 

 toid so-called ' (Ecoj.^ti/chius,^ its date being the early part of the 

 Parkinsonian Age. An (Ecoptychius Grossouvrei, from ' Bajocien 

 superieur, Sully,' has recently been figured and described by 

 'SL. Brasil.^ A specimen of this species has been in my cabinet 

 some 15 years, collected by Mr. P. Stubbington, from Broad 

 Windsor — top beds — evidently from the deposits of the zigzag 

 hemera. I gave it a jMS. name as a new species of (Ecoptychius, 

 But with my present knowledge of homoeomorphous forms I doubt 

 the correctness of the designation. 



The species certainly has a remarkable likeness to the (Ecoptychius 

 refractus^ Bein.,^ which is the type of jS^eumayr's genus. But 

 that is a Kellaways species ; and Grossouvrei^ to belong to the same 

 genus, must have been the ancestor of refractus. This involves 

 the supposition that this peculiar distorted form remained with little 

 alteration or modification for a very long time, during which a 

 whole series of distorted forms ought to be found connecting 

 Grossouvrei and refractus. In my opinion, such direct genetic 

 connexion is doubtful, and I regard the similar shape of these 

 species as the independent results of similar causes. Grossouvrei 

 is apparently the refracted form of Sphoeroceras^ and possibly the 

 final representative of that particular line. Refractus seems to be 

 the distorted form of another series, because it shows what Gros- 

 souvrei does not, a subsulcate periphery,'* so that it is, possibly, the 

 refracted form of a peripherally-sulcate series allied to ParTcinsonia. 

 These species are heterogenetic homoeomorphs. 



This homoeomorphy goes even farther : for Quenstedt figures ' a 



^ In compliment to M. Emile Haug. 



2 Brasil, ' Oeph. uouveaux,' Bull. See. geol. Normand. vol. xvi (1893) p. 45 & 

 pi. iv, figs. 12 & 13. 



^ Reinecke is the author of the specific name, not de Haan, who is generally 

 credited with it. Reinecke forestalled him by 7 years. 



* Tede d'Orbigny. The ribs are distinctly interrupted on the periphery. 



® ' Amm. Schwabisch. Jura,' vol. i (1885), p. 368 & pi. xlvi, fig. f. 



