246 



CEPHALOPODA. 



GONIATITES. 



17. Ammonites lacdnatus. — The Fretted Ammonites, pi. 

 XX.** figs. 8, 9. 



A. lacunatus. Muroliison, Geo. Chelt. p. 105, pi. 11, f. 4, 5. 



Discoidal, with four or five half-concealed, slightly compressed 

 volutions, crossed by rather close, curved, alternately long and 

 short ribs, sometimes anastomosing ; back with a single, nar- 

 row furrow, which is wanting in young specimens ; aperture 

 small, oblong. 



The Lias Shale, Dowdswell Hill. 



18. Ammonites Boblatei. — Boblaye's Ammonite, pi. XX.** 

 figs. 13, 14. 



A. BoUmjei. Murchison, Geo. Chelt. pi. 12, fig. 3. 



Compressed, with five rapidly increasing two-thirds con- 

 cealed volutions ; deeply umbilicate ; volutions crossed by 

 very thick curved ribs, -which project considerably beyond the 

 dorsal line ; these become more flattened on the outer volutions. 



The Lias Shale, Cheltenliam. 



19. Ammonites dissimjlis. — The Dissimilar Ammonite, pi. 

 XX.* figs. 11, 13, 13. 



Inflated, with rapidly iu'jreasing volutions, the smaller ones 

 entirely concealed ; largely umbilicate ; crossed by broad fur- 

 rows, and flattened curved ribs passuig over the thick back, 

 with a few elongated nodules on the inner edges of the volu- 

 tions ; aperture wide and sub-orbicular. 



The Calcareous Grit, Scarborough. 



In the Manchester Museum. 



20. Ammonites calcab. — The Spur Ammonites, pi. XX.* 

 fig. 4. 



Discoidal ; inner volutions entirely concealed ; sides with 

 irregular alternately long and short curved ribs, and a central 

 series of round tubercles ; back with a double keel, consisting 

 of close-set sharp tubercles, each series pointing outwards. 



The Lias, Scarborough. 



In the Cabinet of Thomas Allis, Esq., York. 



21. Ammonites rotifer. — The Wheel-like Ammonite, pi. 

 XX.* figs. 14, 1.5. 



Discoidal, with five moderately rounded, smooth volutions, 

 which are one-third concealed ; a series of close-set ribs pass 

 over the rounded back, and reach nearly the middle of the 

 volutions on either side, where they are met by wide-set, thick 

 ribs, which emanate from tlie inner margins ; aperture nearly 

 oi'bicular. 



The Calcareous Grit, Scarborough. 



In the Manchester Museum. 



23. Ammonites Mulgkavius. — Mulgi-ave's Ammonites, pi. 

 XX.* fig. 16. 



A. Mulgraviiis. Young and Bird, Geo. York. p. 251, pi. 13, 

 tig. 8. 



Discoidal ; umbilicated ; volutions more than half concealed, 

 and rapidly increasing ; internal sides bevelled inwards, the 

 inner edges defined by a pei-pendioular flat margin ; back nar- 

 row, with a central smooth, narrow, and low keel; surface 



covered with a series of elegantly falcated furrows, emanating 

 from the inner edges in extremely fine lines, which gradually 

 increase in width after passing the centre of the volutions. 



The Lias, Lythe, Saltwick. 



23. Ammonites fimbriatds. — The Fringed Ammonites, p. 

 28, pi. XX. fig. 12, and pi. XX.* fig. 8. 



Discoidal, with four cylindrical, rapidly enlarging volutions, 

 the inner ones entirely exposed ; surface with many raised 

 transverse and spiral narrow ribs, dividing it into sub- 

 quadrangular hollow spaces ; the tranverse divisions being all 

 curved, and producing a fringed appearance ; aperture orbicular, 

 provided with an undulating frill. 



The beautiful specimen from which we drew fig. 8, pi. XX.* 

 was obtained in the Lias at Whitby, by my friend James Cook, 

 Esq., of York, and is in his cabinet. Its diameter is ten inches, 

 and the thickness of the outer volution, three and a half inches. 



Gends GONIATITES. — Ion iJitc/(. 



1. Goniatites undulatus. — The Waved Goniatites, pi. 

 XXL* figs. 1, 2, 3, 4, 5. 



G. undulatus. Brown, Tr. Man. Geo. Soc. I. p. 213, pi. 7, 

 figs. 1.2, 3, 4, 5. 



Sub-globose, glabrous, and shining ; crossed by numerous 

 transverse, irregular, undulating, continuous raised lines, which 

 bend downwards as they pass over the ambit ; also provided 

 with deep, straight, transverse constrictions ; ambit rounded ; 

 umbilicus very small, deep, and angulated ; aperture wide and 

 expansive. 



In the very young state this species is destitute of the trans- 

 verse lines and constrictions ; the umbilicus is large, and ex- 

 hibits the volutions. Diameter nine lines, thickness a third 

 less. 



This beautiful species occurs in fragments at Lambert's 

 Clough, near Todmorden, and at Crossbills, near Skipton, 

 Yorkshire. The distinct and bold undulating lines distinguish 

 tliis from all its congeners. 



2. Goniatites inteemedius. — The Intermediate Goniatites, 

 pi. XXL* figs. 6, 7. 



G. intermediui. Brown. Tr. Man. Geo. Soc. I. p. 213, pi. 7, 

 figs. 6, 7. 



Shell discoidal, sub-compressed ; crossed by indistinct, wide- 

 set, continuous, doubly bent undulations, which dip rapidly in 

 an arcuated manner as iliey pass over the sub-cariiiated ambit, 

 which is a little compressed; constrictions regular, broad, 

 shallow, and greatly arcuated on the sides, and in passing over 

 the ambit; volutions tliree, and rapidly increasing ; umbihcus 

 large and deep, with raised angular edges, and exhibiting the 

 three volutions. Septa, the dorsal lobes single, sole-shaped, 

 with a truncated point ; a single, pointed lateral sinus, and two 



