SUB-ORDER B RHIPIDOGLOSSA 443 
Family 1. Haliotidae. Fleming. 
Shell flattened, auriform, with wide aperture, and no operculum. Interior nacreous, 
with a row of perforations on the left outer margin. Marine. Cretaceous to Recent. 
Haliotis, Linn. This, the solitary genus, occurs very rarely fossil except in the 
Quaternary. 
Family 2, Pleurotomariidae. dOrbigny. 
Shell spiral, sub-spherical, turbinate, conic, turreted, or planorboid, nacreous inter- 
nally. Outer lip with a slit, from which a slit-band (the anal fasciole) extends backward, 
traversing all the whorls. The slit sometimes replaced by one or more perforations. 
Operculum horny. Cambrian to Recent. 
Raphistoma, Hall. Spire depressed or completely flattened ; whorls angular 
above. Umbilicus moderately broad ; 
outer lip with short notch on the keel. 
Cambrian to Silurian. 
Pleurotomaria, 
Defr. (Figs. 798- 
802). »Shell 
broadly conical or 

turbinate ; spire Fic. 798. 
: : F IG. 799. 
sometimes high,  Pleurotomaria (Rhephisto- Fic. 7 
mella) radians, Wissm. Pleurotomaria (Cryptaenia) polita, Goldf. Lower 
in other cases de- Keuper ; St. Cassian, Tyrol. Lias ; GOppingen Wurtemberg. 
pressed ; umbili- 
cus present or absent. Outer lip with slit; growth-lines strongly recurved, meeting 
in the slit-band. Silurian to Recent. Four living and several hundred fossil species 
known. Rare in the late Tertiary 
Sub-genera: Ptychomphalus, Bo Mowrlonia, Worthenia, Agnesia, de Koninck ; 
Gosseletina, Ivania (Baylea, de Kon.), Bayle ; Raphistomella (Fig. 798), Zygites, Laubella, 
ah 
i PHM a 
Sarit qh a TEENO 
AMIN 

Fic. 800. es 
Fic. 801. 
Pleurotomaria bitorquata, Des- : 
longchamps. Middle Lias; May, Pleurotomaria subscalaris, Deslongchamps. 
Calvados. Lower Oolite ; Bayeux, Calvados. 1/2. 
Stuorella, Schizodiscus, Kittl; Brilonella, Kayser ; Hesperiella, Holzapfel; Cryptaenia (Fig. 
799), Leptomaria, Deslongchamps (Fig. 802), ete. 
Porcellia, Leveillé (Leveilleia, Newton), (Fig. 803). Shell discoidal, flat, widely 
umbilicate, nearly symmetrical, and all but the first few whorls coiled in the same 
