THE ECHINODERMS OF PORTO RTOO. 
247 
27. Amphiura flexuosa Lyman. 
This species was previously known only from Brazil. The Porto Rican specimen was taken at 
station 6066, on sand and mud, in Mayaguez harbor, at a depth of 162 to 171 fathoms. It answers well 
to the description, except that the next to the lowest arm-spine is bent. 
28. Amphiura stimpsoni Lutken. 
This species was known from the West Indies and Brazil in water of 10 to 35 fathoms. The Porto 
Rican specimen was collected on the reefs at Mayaguez. 
29. Amphiura hihamula, nov. sp. (PI. 14, tigs. 6 to 9.) 
Arms 5, very long and slender. Disk 5 mm. in diameter, clearly indented in the interbrachial arcs; 
arms about 60 mm. long; .\ R=12d. Arms scarcely 1 mm. wide at base. Disk covered with rather 
large smooth scales. Radial shields short and broad, about twice as long as wide, completely separated. 
Upper-arm plates very broadly oval, rounded in front and wider there than behind; about twice as wide 
as long. Arm-spines 6 or 7 (figs. 8 to 9), the uppermost shortest; the fourth and fifth, or fifth and 
sixth, are longest (about equal to the joint) and have 2 prominent little hooks at the tip; all somewhat 
flattened and minutely spiny. As the distal end of the arm is approached, the upper-arm plates 
become smaller and the spines fewer, until at the tips the plates are very small, almost circular, and 
widely separated by the side-arm plates, and there are only 3 spines, subequal and shorter than the 
joint. Under-arm plates almost square, slightly concave in front, more or less convex behind, becoming 
longer and narrower as the tip of an i is approached. Tentacle scales, 2 at base of arm, quite small; 1 
on the proximal, and 1 on the inner side of tentacle. Beyond the first third of arm there is only 1 
scale, the one on inner side of tentacle having disappeared. Oral shields longer than broad, suddenly 
widened at the proximal end. Adoral plates large, almost triangular, meeting within but not without. 
Oral papilke as in typical Amphiura, a pair at the tip of the jaw and one rather large one at the distal end. 
Above and in front of the latter is a small sharp-pointed oral tentacle scale. Genital slits, 2 in each 
interbrachial space. Color of disk above very light gray; arms and mouth parts very pale cream color. 
There is a single very good specimen of this interesting form from station 6050, at entrance to 
San Juan Harbor, on sand and mud in 91 fathoms. Its nearest allies seem to be verticillata Ljn. from 
Galapagos Islands and divaricata Ljn. from the East Indies. Its nearest West Indian ally is apparently 
A. otteri Ljn., but it differs decidedly from that species in the radial shields and in the arm-spines. 
The name hihamula refers to the two little hooks on the lower arm-spines. 
30. Amphipholis goesii Ljungman. 
Previously known from Cape Hatteras southward to Brazil, in water from 14 to 280 fathoms deep. 
The Porto Rican specimens were taken on sandy or, more usually, muddy bottom, in comparatively 
shallow water (4£ to 25 fathoms), but twice at greater depths. It seems to be very common at the 
west end of Porto Rico. Sixty specimens of this species from stations 6054, 6056, 6057, 6058, 6059, 6060, 
6061, 6062, and 6063. The largest has the disk missing, but the arm measures 160 mm. The smallest 
has the disk only 2£ mm. ; the radial shields are scarcely visible, and the oral papillae are of nearly 
equal size. 
31. Amphipholis limbata (Grube). 
This species was previously known only from Rio Janeiro. The Porto Rican specimen, which is 
a very good one, was taken at station 6053, in 4 to 7\ fathoms of water, on fine sand, in San Juan Harbor. 
32. Amphipholis subtilis Ljungman. 
This, like the preceding, has been previously known only from Rio Janeiro. The Porto Rican 
specimens, which are small and badly damaged, were taken at Mayaguez, 2 in shallow water and 1 in 
75 fathoms. 
33. ? Amphiodia planispina (von Martens). 
A single specimen of an amphiuran from station 6065, near Mayaguez, may represent this species, 
but as the disk is wanting, it is impossible to identify it positively. It is clearly an Amphiodia, and 
has 3 very broad and blunt arm-spines; the color is reddish, while the tentacles are dark brown, 
making them very conspicuous. 
