\ 



90 DIBRANCHIATE CEPHALOPODS. 



and spatulate behind. Five species of this genus have been 



described from the Lias. 



h. Beloteuthis. — Pen lanceolate, pointed in front, with two 



small wing-like expansions behind (fig. 475). Six species 

 have been described by Count Mtinster from 

 the Upper Lias of Wiirtemberg. 



c. Phyllotcv.tliis. — Pen corneous, thin, and 

 sub-ovate, slightly concave below and convex 

 above, the anterior end narrow. The known 

 forms are from the Cretaceous. 



d. Leptoteuthis. — Pen horny, hastate, broad 

 in front, pointed behind. A single species 

 is known from the Oxford Clay (Jurassic). 



-c. Besides the above, remains found in the 

 Jurassic rocks have been referred to the liv- 

 ing genera Enoplotcuthis and Onvmastrcplies; 

 ^r and the extinct genus AcanthoteutMs has also 



Rg. iib.—Beiouu- been placed in tliis familv. 



this subcostata. Ju- -^ , r< -r ^ iii /n 



rassie (Lias). £ AM. 4. bEPiAD.E. — internal skeleton (fig. 



447, a) in the form of a broad, laminated, 

 calcareous plate, with an imperfectly chambered apex (or 

 " mucro "). The chambered portion of the skeleton corre- 

 sponds with the " phragmacone " of the Belemnites. The 

 fossil species of this family range from the Middle Oolites 

 upwards, and belong to the following three genera : — 



a. Sepia. — Shell broad and thick in front, laminated, and 

 terminating in a prominent mucro. The fossil forms belong 

 to the Oxford Clay (Jurassic) and Eocene Tertiary, and the 

 genus attains its maximum at the present day. 



b. Spiridirostra. — The shell (fig. 476) in this singular genus 

 consists of a chambered portion or "phragmacone" coiled into 

 a spiral, the volutions of which are separated. This is lodged 

 in a pointed calcareous portion or "rostrum." The only known 

 species of this genus is found in the Miocene Tertiary. 



c. Belo'ptera. — Shell consisting of a nearly straight cham- 

 bered portion or " phragmacone " perforated by a siphuncle, 

 and lodged in a pointed calcareous rostrum which is fur- 

 nished with lateral wings. Two species only of this genus 

 are known, both from the Eocene Tertiarv. It seems 



