50 EXPLANATION OF PLATE 29. 



Fig. 7. Upper surface of Fossil Loligo from the Lias of 

 Lyme Regis. A, A, Barbs of the Pen. B, B, Mar- 

 ginal bands. C, Axis of the Pen. dy upper plate 

 of marginal band, having an unusually corrugated 

 surface, which may be the result of imperfect growth 

 of the transverse fibres ; if fully expanded they would 

 probably have resembled those of the subjacent 

 Plate at d". (Original.) 



d'. Magnified representation of the rugous surface of d. 



d'". Magnified representation of the second plate of the 

 marginal band, Fig. 7. d!'. 



€. Upper surface of second Plate of the shaft of the pen ; 

 here the transverse wavy lines predominate over 

 the vertical straight lines ; but both are visible. 



f. Upper surface of third plate ; here the vertical straight 

 fibres prevail over the transverse wavy fibres. 



Plate 29. V. L pp. 307 and 309. 



Fig. 1. Fossil Loligo from Lias at Lyme, in the collec- 

 tion of Miss Philpot, exhibiting nearly the same 

 structure as figs. 6. 7. at PL 28. and containing be- 

 neath the pen, a very large Ink bag, D. The greater 

 proportionate size of this Ink bag indicates a dif- 

 ference in species from fig. 3. (Mrs. Buckland. 

 Original.) 



Fig. 2. Loligo Aalensis from Lyme Regis shewing the 

 under surface or concave side, and the duct of the 

 Ink bag distended with Ink. A. A. Barbs or fila- 

 ments of the Pen ; B.B. Marginal bands ; C. Axis 

 of Shaft; D. Duct of Ink bag. (Mrs. Buckland. 

 Original.) .^ 



The wavy lines here seen between the Ink bag 

 and the apex of the Pen, are the inferior termina- 

 tions of the successive laminae of growth; each 



