MUSEUM OF COMPARATIVE ZOOLOGY. 223 
Pecten (Pseudamusium) Sigsbeei Datt. 
Plate IV. Fig. 2. 
Valves rather convex, the left one most so; both apparently polished, but 
with microscopic silky concentric strie ; no radiating sculpture, no prismatic 
markings ; anterior auricles well marked, very smal], oblique; posterior auri- 
eles larger, with a broad shallow byssal sulcus but no fasciole or pectinium, 
the markings only of concentric growth lines; color brownish with opaque 
white splashes. Alt. 11.5; lon. 9.1; diam. max. 3.75 mm. 
Two valves were obtained by Sigsbee in 158 fms., Lat. 22° 10’, W. Lon. 
82° 20’, near Havana, Cuba. This little species is very recognizable by its 
plump oval shape, like an apricot stone, and its smooth surface destitute of 
radiating sculpture. 
Genus HINNITEHS Derrance. 
Hinnites Adamsi, n. s. 
Plate V. Fig. 6. 
Shell thin, ashy white externally, internally semi-nacreous ; rounded with a 
comparatively short straight hinge-line ; attached valve unknown ; upper valve 
indistinctly auriculate, rather flat, irregular toward the margin with a small 
pointed but not prominent apex, a little to the right of the middle of the hinge- 
line ; sculpture composed of somewhat irregular radiating coste, not bifur- 
cating but increasing by intercalation toward the margin, where they are much 
crowded; these coste are formed by crowded overlapping rounded scales, like 
biscuit piled one over another, and showing sharp edges only where worn ; 
there are about forty with a somewhat smaller number of intercalary ones ; 
the concentric sculpture is composed of ill-defined lines of growth, and the 
whole surface is microscopically granulose; interior polished, silvery, repro- 
ducing the external rugulosities ; muscular impressions invisible; cartilage pit 
triangular, distinct, hinge-line smooth, margin nearly simple. Lon. of shell, 
28.0; of hinge-line, 13.0 ; height of shell, 30.0 mm. 
Station 227, off St. Vincent, in 573 fms., fine sand and gray ooze ; the bottom 
temperature 40°.5 Fahrenheit. 
This shell has an unmistakably abyssal facies and seems to belong to the 
genus Hinnites. It is named in honor of Prof. Charles B. Adams, of Amherst, 
to whom so much of our knowledge of the fauna of the West Indies and 
Panama is due, and who was among the first of American naturalists to recog- 
nize the variability of what we call species, and the close relations which exist 
in nature between forms admitted by naturalists to be of “ specific ” value, or, 
in other words, which have obtained a temporary equilibrium of characters 
which they transmit to their descendants. 
