download pdf

SPONDYLIDAE 369
are attached to rocks and become quite massive like Spojidyhis. For con-
venience, we are considering it a full genus.
Himjttes multirugosiis Gale Giant Rock Scallop
Aleutian Island to Lower California.
Plate 29a
Up to 8 inches in length. A heavy massive shell characterized by the
early "Chlamys-Hke" shell at the beaks. Interior white with a purplish hinge
area. Attached to rocks by the right valve. The ^2-inch long young are
almost impossible to separate from some species of Chlainys, except when
they show a mauve spot on the inside of the hinge line on each side of the
resilium pit, or if they show signs of distortion or a mottling pattern of
color on the outside of the valves. Some vouno- are bright-orancre. A common
species. Formerly known as H'mnites gigante7is Gray. This is a regrettable
name change which I have followed, since leading workers on the Pacific
Coast have adopted it.
Fa77nly PROPEAMUSSIIDAE
Genus Propeaviusshmi Gregorio 1883
Propeavitissmm poiirtalesiaimm Dall Pourtales' Glass Scallop
Southeast Florida and the West Indies.
Plate 27c
/4 inch in length. Valves very slightly convex. Shell extremely thin
and transparent (hke thin mica flakes). Each valve reinforced inside with
about 9 rod-like, opaque \\'hite ribs. Exterior of one valve is smoothish, the
other valve with numerous, microscopic, concentric threads. Common off-
shore. Frequently dredged off Aliama by amateurs. There have been a
number of other species described, some of which may only be forms of this
variable species.
Fmjiily SPONDYLIDAE
Genus Spondylus Linne 1758
Spondylus americanus Hermann Atlantic Thorny Oyster
South half of Florida and the West Indies.
Plate 36b
3 to 4 inches in size. Spines 2 or less inches in length, usually standing
fairly erect. Color variable: white with yellow unbones, red or purple;
sometimes all rose, all cream or all pink. The young are much less spinose,
and might be confused with Chama which, however, does not have the ball-
and-socket type of hinge. Beautiful and large specimens are found clinging