544 UNIO 
pears a little more sulcate than most of the specimens I have 
seen, but it agrees otherwise in all the characters. The species 
is more solid, more inflated and less rhomboid than U. turtonz; 
it is shorter and more evenly elliptical than U. pictorum or 
tumidis. 
UNIO MODIOLA Preston. 
“Shell elongaiely oblong, somewhat curved, solid, covered 
with a chocolate coloured, laminiferous periostracum, both 
valves concentrically striate; umbones large, but not promi- 
nent, somewhat coarsely corrugate; dorsal margin slightly 
arched ; ventral margin curvedly excavated in the median pos- 
terior region ; anterior side somewhat produced, rounded above. 
sloping below; posterior side produced, rounded; cardinal 
teeth rather anteriorly situate, triangular, erect; lateral teeth 
anteriorly very short, posteriorly elongate and abruptly ter- 
minating; anterior adductor scars deeply impressed; poste- 
rior scars slight; interior of shell very slightly iridescent, sculp- 
tured with fine, irregular ridges somewhat resembling the 
marks of coarse finger prints. 
Long. 45, lat. 86 mm.” (Preston). 
Type locality, River Tigris. 
Unio modiola Preston, Rec. Ind. Mus., VII, 1912, p. 286, pl. 
Vit, figs. 1-2. 
Unio HUETI Bourguignat. 
Shell almost evenly long elliptical, somewhat inflated, sub- 
solid, inequilateral ; beaks slightly elevated, not full, their sculp- 
ture not known; posterior ridge low, rounded, ending behind 
in a rounded point just below the median line; anterior end 
rounded ; base line slightly curved; surface decidedly concen- 
trically sculptured; epidermis yellowish or fuscous green; 
pseudocardinals subcompressed, ragged; laterals long, slightly 
curved; anterior muscle scars deep. 
Length 68, height 33, diam. 21 mm. 
Upper Euphrates in the Pashalic of Ergeroum, Armenia, 
Asia Minor. 
