On "(7 Neio Classification of Ammonites."' 4al 



clouded ; abdomen variegated with white and yellow. Head 

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

 white pile ; the palpi pale testaceous. The posterior maro'in 

 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 ; the 

 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, 

 reddish 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 tlie first apical cell. 

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

 insertion of the antenna3 and the clypeus covered with silky 

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

 thorax silvery ; the anterior tibiae 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 oontimipd.] 



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

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



As to M. Kcferstein's theory that the AptT/chus 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 Aptychus^ 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 this 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 liabits of recent Mollusca, 

 and is, indeed, entirely opposite to all my experience as a 

 student in the structure and devel()i)ment of shells. 



29* 



