150 Mr. A. Hancock^s Notes on Buccinum undatum. 



fourteen days in chrysalis at the seasonal temperature. The spe- 

 cimens bred by myself were developed in somewhat more than ten 

 days, when the mean of the lowest temperature during that period 

 was 71°-06 F. and the highest 75°-5 F. 



In conformity with this, I found that V. urtica is the best 

 species for experiment, owing to its not requiring so high a tem- 

 perature for development. On Plate VIII. fig. 3 is represented 

 one of the specimens of V. Id which were the subjects of expe- 

 riment. It has the left mesothoracic leg reproduced precisely in 

 the same stage of development as the new limb in Panesthia. 



EXPLANATION OF PLATE VIIL 



Fig. 2. Inferior surface of Panesthia ? (magnified two diameters) with 



the left posterior leg reproduced. 



Fig. 3. Inferior surface of specimen of Vanessa I'd, from which the left meso- 

 thoracic leg was removed at the end of the fourth change of the 

 larva. 



XVII. — Notes on Buccinum undatum. 

 By Albany Hancock, Esq. 



During a short residence at Cullercoats in 1841, I paid some 

 attention to the various forms of Buccinum undatum, with the 

 view to determine whether the several reputed species of this pro- 

 tean shell should retain the rank to which they have been elevated 

 by some naturalists/ or be reduced to mere synonyms. 



In fm'therance of this object I collected extensive suites of the 

 different varieties, and soon ascertained that there are three well- 

 marked forms, which on this coast at least do not appear to run 

 into each other, and which are procured from distinct localities 

 and from different depths of water. These three forms are distin- 

 guished from each other by their general shape and habit, and 

 not merely by the undulations and strise, characters of little im- 

 portance in this portion of the genus, and on which conchologists 

 have placed too much reliance. In all the three varieties the 

 undulations and strise are very variable ; the form of the mouth 

 and columella, however, is constant throughout, never losing the 

 essential characteristics, which are retained in the most robust 

 and coarsely undulated as well as in the most deUeate and 

 smooth. 



At first I was inclined to think it probable that these three 

 varieties might prove to be distinct species ; but after a length- 

 ened and careful investigation I feel satisfied that they are mere 

 varieties, though of permanent and strongly-marked characters, 

 resulting from locality and depth of water. The animals of these 

 three varieties do not appear to vary. 



It is evident from what has been said respecting the undula- 



