MOLLUSCA— CEPHALOPODA 



PHYLUM VI 



682 



Distribution world-wide , most abimciant ^i , ^^ .^^^^ ^^^^.^ ^^ ^^^^ j^^^^ 



"* a a ?> and Cretaceous, this genus 



®S) »^ ig scarcely less important 

 than the Amnionites. 



Subgenera : Pachyteuthis 

 Bayle (Fig. 1318, A). Guard 

 perfectly smooth. Confined 

 to tbe Lower Lias. B. acutus 

 Mill. 



Megateuthis Bayle {Dac- 

 fA/loteuthis Bayle, PaxiUosi) 

 (Fig. 1318, B). Apex of 

 the guard with two or tbree 



Fio. 1317. 

 Belemnites {Duvalia) 

 dilatatus Blv. Neo- 

 comian ; Justithal, 

 Lake of Thuti, Switzer- 

 land. 



I 



Fig. 1318. 



A, B. (Pachyteuthis) acutus Miller. Lower 

 Lias ; Lyme Regis, Dorsetshire. B, B. {Mega- 

 teuthis) paoällosus Schloth. Middle Lias ; Metzin- 

 gen, Würtemberg. C, B. {Pseudohelus) bipartitus 

 Blv. Lower Cretaceous ; Castellane, Basses 

 Alpes, a, h, c, Dorsal and ventral aspects and 

 cross-section, l/j. D, B. {Belemnopsis) canalica- 

 latus Schloth. Inferior Oolite ; Würtemberg. 

 E, B. (Belemnojms) hastatus Blv. Oxfordian ; 

 Dives, Calvados. 



Fig. 1319. 

 Belemnites {Actinocamax) qnad- 

 ratus (Blv,). Upper Creta- 

 ceous ; Germany. A, Dorsal 

 View of guard with defonned 

 phragmacone projecting from 

 alveolus. B, Ventral aspect of 

 guard. C, Alveolus from above 

 (after Schlüter). 



usually Short grooves. Middle Lias to Lower Cretaceous. B. paxülosus and B. giganteus 

 Schloth. ; B. elongatus Mill. ; B. subquadratus Roem., etc. 



Belemnopsis Bayle (Hibolühcs Montf. , Gastrocoeli, Canaliculati, Hastati) (Fig. 1318, D, E). 

 Guard with deep and usually long ventral furrow extending from alveolar niargin toward the 

 apex, with or without dorso-lateral lines. Middle Jura to Middle Cretaceous. B. canaliculatus 

 Schloth. ; B. absolutus Fisch. ; B. unicanaliculatus Zeit. ; B. minimus Lister. 



Pseiulobelus Montf. (Bipartiti) (Fig. 1318, C). Guard thin, slender, with deep dorso- 

 lateral grooves, with or without ventral furrows. Upper Lias to Lower Cretaceous. B. exilis 

 d'Orb. ; B. bipartitus Blainv. 



^ Actinocamax Miller {Gonioteuthis Bayle) (Fig. 1319). Guard cylindrical, submucronate, 

 with Short but very deep ventral furrow ; anterior end foliaceous, and very liable to dissolu- 



