CEICK : ON STYRACOTEUTHIS OPJEXTALIS. 277 



But he did not figure the genus. The type-, and the only known 

 species ( V. occidentalism from the Eocene of Brittany) was subsequently 

 figured by Vasseur' (pi. i, figs. 8-15) in an incomplete work issued in 

 1881,2 l3y ^ Y-d.v\ Fischer in 1882,3 i^y ^ Cossmann in 1895,* and 

 by MM. Cossmann & Pissaro in 1900.^ In this genus the guard is 

 small, conical, narrow, having the form of Dentalium, and is straight, 

 or very feebly curved ; its external surface is ornamented with 

 a number of longitudinal grooves ; the phragmocone is more than oue 

 half the length of the guard and has an elliptical cross-section ; the 

 septa are oblique, directed backwards towards the siphuncular side, 

 and provided with a subangular siphonal lobe ; the septal necks exteud 

 from one septum to another. The type-species is described by Munier- 

 Chalmas as having from 8 to 10 longitudinal grooves, with other 

 secondary ones interpolated between them. Zittel, however, in his 

 definition of the genus ("Handbuch der Palseontologie," Bd. i, 

 Abth. 2, Lief, iii, 1884, p. 509) states that the shell was ornamented 

 with three longitudinal furrows extending from the apex (" mit 3 

 von der Spitze ausgehenden Langsfurchen "), a statement which is 

 repeated in the first (1895, p. 442) and second (1903, p. 476) editions 

 of his " Grundziige der Palseontologie." The statement is not borne 

 out by any of the examples that the present writer has examined ; 

 they all possess considerably more than three rather deep grooves 

 which extend from the apex and disappear towards the anterior part 

 of the guard, whilst between these are interpolated finer grooves 

 which anteriorly are entirely replaced by small irregular depressions, 

 giving to the surface of the guard the appearance of shagreen. 



The Arabian specimen is much larger than this genus ; its two 

 longitudinal grooves are deepest at the alveolar margin, and do not 

 extend to the posterior extremity, whereas in Vasseuria the longi- 

 tudinal grooves extend from the apex and die out on the alveolar 

 region ; Vasseuria also does not possess any dorso-lateral depressions. 



While having affinities with both Bayanoteuthis and Vasseuria, the 

 present specimen may also be compared with the Upper Cretaceous 

 genus Bekrmiitella, d'Orbigny.® Well-preserved examples of Belemni- 

 tella mucronata'^ possess, on each side, a double dorso-lateral groove, 



' " Recherches geologiques sur les terrains tertiaires de la France occidentale." 

 Paleontologie par G. Vasseur. Atlas : pis. i-iii and v-xi. Cossmann states 

 that he possesses also plates iv and xix. 



- M. Cossmann : Bull. Soc. Sci. Nat. de I'ouest de la France, tom. v (1895), p. 159, 

 footnote 2 (= " Mollusques eoceniques de la Loire-inferieure," torn, i, fasc. 1, 

 p. 3, iootnote 2). 



3 " Manuel de Conchyliologie," fasc. iv (1882), p. 359, fig. 137. 



* Bull. Soc. Sci. Nat. de I'ouest de la France, tom. v (1895), p. 167, pi. v, 

 figs. 10-13 (=" Mollusques eoceniques de la Loire-inferieure," tom. i, fasc. 1, 

 1895, p. 11, pi. i, figs. 10-13). 



6 Bull. Soc. geol. Normandie, tom. xix (1898-1899), p. 21, pi. i, fig. 23 (1900). 



6 D'Orbigny: Pal. Franc;., Terr, cret., tom. i, Ceph., 1840-42, p. 59. 



'' See D'Orbigny, op. cit., pi. vii, figs. 1-3 ; C. Schliiter, Palscontographica, Bd. xxiv, 

 pi. Iv, figs. \a, b, c\ and D. Sharpe, Foss. Moll. Chalk (Mon. Pal. Soc), 

 pt. i (1853), pi. i, figs. 2a, b (the dorso-lateral grooves are indicated in these 

 figures, but the vascular impressions are very imperfectly indicated m fig. '2b). 



VOL. VI.— .JUNE, 1905. 20 



