32 STRIAX MOLLUSCAX FOSSILS. 



shows a semblance of a beak. So, too, in the original figures of A. brevis* Mor- 

 ris and Lycett (Moll. Gr. Obi., Pt. I, p. 101, PI. viii, figs. 13, 13 a, b, 1850.— 

 there named Cijlindrites brevis) appears what might be mistaken for an anterior 

 canal. In the latter case, however, the figures are side views, and give a 

 false impression of the anterior of the shell; for a front view of the specimen 

 afterwards figured in the Supplement of the same work (PI. xli, fig. G, 1863), 

 exhibits the " aperture evenly rounded in front," which by all authorities is 

 regarded as a constant character of the genus. The original of this figure 

 (from the Great Oolite of Kirtlington, near Woodstock. Oxfordshire), the only 

 adult specimen known up to the date of Morris and Lycett's Supplement, 

 has been kindly lent to us by the collector, Mr. J. F. Whiteaves, Paleontolo- 

 gist of the Canadian Geological Survey. Of all Actaeonince, this species has 

 the closest general resemblance to the species of the group here considered. 

 Like them it is posteriorly truncate, and has its sides flattened ; but its aper- 

 ture, the lifting of part of the last whorl above the plane of the spire, the 

 rounding of the margins of the truncate convolute whorls, and the smooth 

 surface, as seen in PI. iii. figs. '2 a, b, e (drawn anew for this paper from the 

 specimen itself), are in strong contrast with the corresponding parts of 

 Colostracon. 



Without wishing to lay special stress upon the form of the spire, one of 

 the most variable of characters,! we may yet note that forms like A. concav«,% 

 A. subabbreviata, A. Caumoniu, d'Orb., and the various species of Mieria, — with 

 which the Abeih species will most naturally be compared, — present posterior 

 extremities (vertices) very unlike those of the latter. In fact, the only 

 known shell which exhibits a vertex as cleanly cut as theirs, is Eaphisloma 

 striatum (Emmons) Hall, the subtrigonal aperture and deep open umbilicus 

 of which remove it far from Colostracon. 



In CtfUndrites cylindricus Morris and Lycett (op. cit., Pt. I, PI. viii. 

 figs. 19 a, b, c), the cylindrical form and the truncate and acutely margined 

 vertex make the nearest approach to the Abeih species. But the vertex- 

 is considerably concave, and of the imperfect anterior part (base) only side 



* Is this mil identical with Orthostoma conulm Bi vigne r, Statisque Geologique el Paleontologique du 

 Departemenl de la Meuse, p. :«. PI. xxiv, figs. L6, 17. lv">- 7 ': i 



i We are well aware that a continuous series of dctaonirue maj l>r traced From forms which have Uie 

 spire plane, or evi a :i little immersed, i" those which have the same slightlj or even stronglj elevated. 



J Formerlj regarded as a fossil Conus. See the original " Memoire sur Irs Cones fossiles des Terrains 

 secondares du Calvn<l<. r n I ml. ■. lii'slon^rliamps," Mt'm. ilc la Socie'te' Linneenne de Noruiandie, \ II. 

 pp. 138 I iO L839 42. 



