HALIOTIS. 75 



WEINKAUFF in System atisches Conchy lien Cabinet von Martini 

 u. Chemnitz, 2d edit., 1883. Most of the figures are very poor, but 

 the text is superior to the other works. The author had not, how- 

 ever, seen nearly all of the species. 



In neither of these works are the species arranged systematically. 



Synopsis of Genera and Sections. 



Genus HALIOTIS Linne, 1858. 

 Characters those of the family. 



Section HALIOTIS s. sir. 

 Shell oval ; the foot projecting only a short distance behind it. 



Section PADOLLUS Montfort, 1810. 



Shell rounded, depressed, having a sulcus parallel to the row of 

 holes. 



Section TEIXOTIS H. & A. Adams. 



Shell very long and narrow, smooth ; foot of animal projecting a 

 greater distance behind it than in Haliotis s. sir. 



Genus HALIOTIS Linne, 1758. 



Haliotis LINN, Systema Naturae x, p. 779, 1858 (first species H. 

 midce) ; and of authors generally. Padollus MONTF., Conch. Sys- 

 tem ii, p. 114. Sulculus H. & A. ADAMS, Gen. Rec. Moll, i, 

 p. 443. 



The principal characters for distinguishing the species are the 

 outline of the shell, which is either equally curved on the two sides 

 or straighter on the right margin ; the convexity of the back, which 

 may be carinated or rounded at the row of holes ; the sculpture ; 

 the position of the spire ; the color of the inside ; smoothness or 

 roughness of the muscle-scar ; width and slope of the columellar- 

 plate ; and within rather wide limits the number of open holes. 



NOTE. The measurements are taken as I have directed for the 

 species of Gena (see bottom of page 37 ; and pi. 2, fig. 20). The 

 distance from apex to margin should be measured in 'a plane parallel 

 to the plane of the peristome, as one would measure it on a figure of 

 the dorsal surface of the shell. 



It is convenient to segregate the numerous species of Haliotis into 

 groups ; and the following is offered as a preliminary arrangement: 



