CLASS GASTROPODA 
263 
equal sculpture, the tail valve with the mucro central and a little projecting. 
Interior light blue, with darker stains at bases of the sutural laminae and 
behind the rather strong blue-white callus. Sinus and sutural laminae as 
in Hartwegii. Slits in valve i, 8; valves ii-vii, bilobed. All teeth longer 
than the narrow, porous eaves. Girdle narrow, black or with small whitish 
spots, leathery, very minutely papillose. Length, 23; breadth, 11 mm. 
(type). (Pilsbry.) 
Type in Philadelphia Academy of Sciences. Type locality, San Fran¬ 
cisco, California. 
Range. Seward, Alaska, to San Pedro, California. 
Described as Trachydermon (Cyanoplax) raymondi Pilsbry. 
Subgenus Spongioradsia Pilsbry, 1893 
Lepidochitona aleutica Dali, 1878 
Proceedings of the United States National Museum, 1:1. Tryon and Pilsbry, Manual 
of Conchology , 14:85 and 15:65; PI. 15, figs. 30-33. 
T. t. parva, rufo-cinera, oblonga, fornicata; jugo acutissimo; mucrone 
submediano, apicibus prominentibus; areis lateralis inconspicuis; tota su- 
perficie quincuncialiter minute reticulata; intus, valv. ant. 16-, post. 11-, 
centr. 2-fissatis; dent, parvis, perspongiosis, late separatis; subgrundis 
spongiosis, curtis; sinu parvo; zona squamulis minutis obsita. Long., 6; 
lat., 3 mm. (Dali.) 
Shell small, rufous-ashen, oblong, vaulted, the jugum very acute; mucro 
submedian; apices prominent; lateral areas inconspicuous, entire surface 
minutely reticulated in quincuncial pattern. Interior: anterior valve with 
16, central with 2, posterior with 11 slits; teeth small, very spongy, widely 
separated; eaves spongy, sinus small. Girdle beset with minute scales. 
(Dali.) (Tryon and Pilsbry, Manual of Conchology.) 
Type in United States National Museum. Type locality, Western 
Aleutians. 
Range. Aleutian Islands. 
Described as* Trachyradsia aleutica Dali. 
Genus NUTT ALLIN A Carpenter, 1873 
Shell elongated, valves projecting anteriorly; mucro posterior, elevated; 
laminae acute, smooth, elongate; central valves bifissate; sinus not lami¬ 
nated, planate; girdle spinose. Differs from Acanthopleura in the smooth¬ 
ness of the sharp teeth, in their great length and Radsioid slitting; in the 
throwing forward of the rest of the shell, as in Katherina, and in the deep 
[ 865 ] 
