CHAP. XI.] 



HALIOTIS. 



287 



FIG. 75. Abnormal horns of Roebuck (Capreolm caprea), No. 438. 

 by rne the horns were fixed upon heads modelled in plaster.) 



(When seen 



441. 



442. 



PERFORATIONS OF SHELL OF Haliotis. 



Haliotis gigantea (Japan) having two rows of perforations in the shell. In 

 addition to the ordinary row of perforations, of which 12 were present in this 

 specimen, there was a series of 8 additional perforations which began within an inch 

 of the apex. Of the normal series the last four remained open, but all the perfora- 

 tions in the abnormal row were closed with nacre. Specimen in Brit. Mus. SMITH, 

 E. A., Ann. and May. of N. H., 1888 (1), p. 419. 



Haliotis : two specimens, of different species, in which the perforations were 

 entirely absent, their place being taken by a continued convex, spiral rib, like the 

 second rib of Padollus. "Probably in this individual the mantle 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 Emarginulce, or Scuta." (JKAY, J. E., Proc. 

 Zool. Soc., 1856, p. 149. 



** albicans : several specimens in which the perforations were united to form a 

 continuous slit. The appearances were so uniform that Gray was disposed to think 

 that these specimens might represent a new genus, but on comparison with types 

 they seemed to belong to the species named. In some fossil genera (Scissurella) the 

 perforations are replaced by a more or less continuous slit over the mantle. The 

 specimens in question were greatly eroded and had a diseased appearance, ibid. 

 Plate. 



