On "a Nmi) Classification of Ammonites.'^ 451 



clouded; abdomen variegated with. white and yellow. Head 

 scarcely as wide as the thorax, and both covered witli silky 

 white pile ; the palpi pale testaceous. The posterior margin 

 of the prothorax arcuate ; the metathorax longitudinally de- 

 pressed ; the wings fusco-hyaline, a darker cloud occupying 

 the marginal and second and third submarginal cells ; tlie 

 anterior legs in front and their tarsi ferruginous. Abdomen 

 subsessile, having a fine silky pile ; the apical margins of the 

 first and second segments, and the following segments entirely, 

 reddisli yellow ; a large pale yellowish-white macula on each 

 side of the second segment. 

 Hah. Para. 



Agenia cursor. 



Male. Length 5^- lines. Black, with a fine silky pile ; legs 

 elongate, the posterior pair longer than the insect ; anterior 

 wings dark fuscous, and having a clear hyaline space that 

 occupies the three discoidal as well as the first apical cell. 

 Head transverse, as Vide as the thorax ; the face below the 

 insertion of the antennse and the clypeus covered with silky 

 pile. Thorax : the sides, beneath, and the apex of the meta- 

 thorax silvery ; the anterior tibiaj beneath and the tarsi obscure 

 ferruginous. Abdomen : the first segment forming a petiole 

 which is longer than the metathorax ; the other segments have 

 a blue tinge. 



Hah. Para. 



[To be continued.] 



LIII. — Ohservations on M. Favre's Paper on a New Classi- 

 fication of Ammonites. By Dr. J. E. Gray, F.R.S. &c. 



As to M. Keferstein's theory that the ApUjclius is ''a pro- 

 tecting organ of the nidamentary glands of the female Ammo- 

 nite," which M. Favre considers certain — and he further goes 

 on to say, " the soft tissue of this gland has a great resem- 

 blance in its various parts to the structure of the different 

 types of AptychuSj and the form of the Aptyclms corresponds 

 very well with that of the outer part of this gland " (p. 366) — • 

 I do not offer any decided opinion on tliis extraordinary 

 theory, as I have never studied the question ; at the same 

 time I may observe that it is not supported by any thing I 

 have observed in the structure or habits of recent Mollusca, 

 and is, indeed, entirely opposite to all my ex])erience as a 

 student in the structure and development of shells. 



29* 



