64 AMERICAN JOURNAL 



NOTE ON THE INTERNAL STRUCTURE OP 

 MEGASPIRA. 



BY THOMAS BLAND. 



Lea gave the generic name of Merjaspira (Obs. II., p. 21,) to 

 Pupa elatior, Spix, which, with the allied species elata, Gould, 

 was placed by Pfeiffer (Mon. II. and III.) in 

 the genus Balea. In his last Supplement 

 (Mon. IV.), Pfeift'er adopts 3Ie;jas2)ira, consid- 

 ering it entitled to generic rank. 



In a late examination- of the internal 

 structure of species of CylindreUse, I opened 

 a specimen of Megasjiira elatior, and finding 

 it extremely curious, and, so far as I can 

 learn, hitherto unnoticed by authors, I now 

 describe it. 



In the centre and on the under side of the 

 septa, beginning at about the twelfth whorl from the apex, 

 there is a raised lamina, which is continued to the aperture, 

 where it terminates on the parietal wall. 



A single lamina revolves on the axis in the upper whorls, but 

 lower down, where the septal lamina commences, there are two 

 or three, the lowest projecting obliquely, and with a sinuous 

 margin, which is obsolete on the last whorl. These axial 

 laminre terminate on the columellar margin of the aperture. 

 Within several of the lower whorls, on the septa, there are 

 two or three curved lamellse, at right angles with the axis, 

 some of them armed with a hook, the point of which is di- 

 rected towards the axis. 



The transverse lamellse and lamina, of peculiar form, with 

 sinuous margin, I have not observed in any species of Gylin- 

 drella. Of the alliances of Megaspira with other genera, 

 shown by the buccal plate and lingual band, I have not seen 

 any notice. 



