BARNACLES OF JAPAN AND BERING SEA. 
Si 
the spur of the tergum. It is apparently as distinct a form as several which are ranked as species, but 
without a large series the constancy of the differential characters can not be tested. I have therefore 
ranked the Japanese form temporarily as a subspecies. The type is a unique individual which had been 
wholly overgrown and filled up with the sponge-host, but with the walls and opercular plates complete 
and perfect. 
Genus TETRACLITA Leach, 
Tetraclita porosa (Gmelin). 
Locality: Matsushima, on shore. 
Genus PACHYLASMA Sowerby. 
Pachylasma crinoidophilum, new species. [PI. xvii, fig. i-ii ] 
Cotypes no. 38675, U. S. National Museum. 
Type locality: Albatross station 4934, off Kagoshima Gulf, in 152 fathoms. 
A species somewhat related to P. aurantiacum Darwin. Base apparently membranous, walls solid, 
not porous. The basal contour is oblong, the ends elevated to conform to the shape of the supporting 
crinoid stem, on which the barnacle always sits lengthwise. The carina rises vertically, the other plates 
slope inward more or less. Rostrum and rostral latera white, carina, carinal latera and tips of the 
opercular plates pink tinted. All of the plates are thin and without radii. The parietes have a fine, 
indistinct sculpture of short, irregular impressions vertical to the faint lines of growth. The alae have 
very oblique, wide-spaced grooves. The carina and the median latera are large plates, the others being 
much smaller. 
The rostrum and rostral latera are narrowly triangular, united by linear sutures (pi. xvii, fig. 3, r., r.l.). 
Internally the rostrum is glossy and slightly ridged transversely in the upper two-thirds (fig. 6). It has 
narrow alae on both sides. The rostral latera are about as wide as the rostrum at their bases, and 
obliquely triangular, without alae (pi. x, fig. 7, interior view). The median latera (pi. xvii, fig. 2, m. /.) 
are very large, with triangular parietes and an ala of irregular shape. Inside (pi. xvii, fig. 8) the apical 
portion of the plate is slightly ridged transversely, the ridges opaque-white; a radius is faintly indicated’ 
The basal margin of the plate is sharp and smooth. The carinal latera (pi. xvii, fig. 2, c. 1 .) are quadran- 
gular, about twice as long as wide, and externally are divided by a diagonal ridge into parietal and 
alar areas. Internally there is an obliquely ridged area near the beak (pi. xvii, fig. 9). 
The carina (pi. xvn, fig. 2, c.) is recurved at the apex, V-shaped as viewed from above. Outside 
there is a rather narrow, triangular parietal area, and two much larger triangular alas. Inside more than 
half of the plate is transversely ridged, the ridges white. 
Length of base 9, width 6.2, height of carina 7 mm. 
The scutum (pi. XVII, fig. 4, 5) is triangular, the width half of the length, marked externally with 
narrow, widely spaced transverse grooves. Inside the articular ridge is well developed, nearly as long as 
the tergal border of the plate. Articular furrow narrow but rather deep. The apical part of the plate is 
transversely ridged. The tergum (pi. xvn, fig. 10, 11) has a strong ridge along the scutal border, and is 
concave near it. The surface is marked with lines of growth and spaced grooves. Some radial lines 
are weakly sketched. Internally there is a very wide but short articular ridge and a deep articular 
furrow. There is a group of sharp crests for the depressor muscle, projecting as small teeth at the lower 
border of the plate. The tergum has a truncate shape at the apex, and is marked internally with 
arcuate ridges there. 
The mandible (fig. n, E) has three long, acute teeth and a blunter, multispinose lower point. It 
is somewhat profusely hairy, as shown in the figure, the hairs projecting below the lower point. 
There is also a patch of hairs on the upper margin. 
The maxilla (fig. 1 1, B) has an irregular, step-like edge, with numerous spines, and is hairy on the 
upper and lower borders. The first cirrus (fig. n, C) has short unequal rami of 9 segments, which are 
very profusely hairy on the inner face, much less so outside. The second cirrus is similar but larger. 
The rest of the cirri are quite long, with three pairs of long and one of very short spines on each segment, 
and a tuft of several spines at each suture posteriorly (fig. 1 1, A). Cirrus vi (fig. 1 1, F) has rami of 22 
48299° — Bull. 29 — ri 6 
