Miscellane(ms. 349 



I am inclined to believe that the slit in the specimens is to be 

 considered as the imperfect filling-up of the shelly matter between 

 the usual perforations, caused by the eroded and evidently diseased 

 state of the specimens. 



The interior of the shells is marked with a very rough tubercular 

 muscular scar, which is not to be observed in perfect specimens ofHali- 

 otis albicans ; but this will be found to be uniformly the case with 

 most specimens of Ear-shells which have an eroded or worm-eaten 

 outer surface, even in species which have a scarcely marked scar in 

 their perfect or normal condition ; so that this difference, like the 

 slit, appears to depend on the state of the shell and the animal 

 which formed it. 



The interior of the shell presents a further peculiarity, but this is 

 evidently caused by the same effects as the roughness of the muscu- 

 lar scar and slit on the branchial ridge, viz. there is a more or less 

 deep broad groove on the inner surface between the slit and the sub- 

 central muscular scar, which is more or less marked with regular 

 cross grooves, and they are evidently impressions of the outer surface 

 of the two branches of the gills. 



Only one of the specimens I have seen shows any indications of 

 the outer surface of the shell, and in that it only forms a band about 

 one-fourth of an inch wide on the edge of the outer lip ; it is pale, 

 greyish, and concentrically striated, like the surface of the normal 

 specimen of Haliotis albicans. 



This kind of monstrosity was to be expected, as the mantle of the 

 animal is slit under the perforations on the shell ; and we have in 

 Scissurella and in several fossil genera the perforations replaced 

 by a more or less continued slit over the mantle. I have never 

 before seen an Ear-shell with more than two holes united into a short 

 slit by the absence of the shelly matter between them ; but when we 

 examine the Haliotis albicans, the existence of the more distant ex- 

 terior groove renders it the species in which one would more readily 

 expect such an abnormal formation to occur. 



I have seen two specimens of two species of Haliotis, which ex- 

 hibited just the converse deformity, being without any appear- 

 ance of the series of perforations, the place of the holes being occupied 

 by a continued convex spiral rib, like the second rib in Padollus. 

 Most probably in this individual the mantle of the animal was without 

 any slit, and hence the malformation, the water being admitted to 

 the gills by the slight notch in front of the ribs, as in some Emar- 

 ginulce or Scuta. — Proc. Zool. Soc. May 27, 1856. 



PERFORATED STRUCTURE OF RHYNCHONELLA GEINITZIANA. 



To the Editors of the Annals of Natural History. 



Belmont near Galway, March 10, 1857. 

 Gentlemen, — I am much gratified to learn from your last Num- 

 ber that Dr. Carpenter has examined some Russian specimens of 

 Rhynchonella Geinitziana ; inasmuch as his examination appears to 

 confirm my suspicion that the German shell, so called, is "a different 



