THE ECHINODERMS OF PORTO RICO. 
245 
diameter, and the arms are 75 mm. long with spines 7.5 mm. The whole structure is very delicate, 
and the dark longitudinal stripe on the arm is very conspicuous. Of the other specimens 2 are from 
station 6067 and 2 from station 6079. 
19. Ophiocoma echinata L. Agassiz. 
This large brittle-star is very common from Bermuda and Florida southward to Brazil, occurring 
under and among rocks and coral along shore and on the reefs. It reaches a diameter of 32 mm., with 
arms 4 to 5 times as long. The color varies considerably; the disk may be uniform brown or black, or 
it may be more or less blotched and spotted with gray or white; the arms are usually black. There 
is also much variation in the size of the arm-spines. 
One-fifth of the collection is made up of specimens of this large and very common species. Of 
the 109, more than half were collected at Ponce and the remainder are from Fajardo, Ensenada Honda 
(Culebra), Caballo Blanco, and station 6096. Mr. Gray collected a large number of this species at San 
Juan. 
20. Ophiocoma pumila but ken. 
Smaller than the preceding, the disk seldom exceeding 15 mm., but found in similar situations 
throughout the same range. The colors vary somewhat, but the banded arms are very characteristic. 
Sixteen small specimens of this species were collected at Ponce and Ensenada Honda (Culebra), 
and at stations 6076, 6077, 6080, 6095, and 6098. Mr. Gray took one specimen at San Juan. 
21. Ophiocoma riisei Lutken. 
Found with O. echinata, from which it is easily distinguished by the rusty-red appearance of the 
underside of the arms. It is less variable in color, the disk being uniformly black or brown. It has 
been taken in deeper water, even up to 200 fathoms. 
No specimens of this common West Indian species were taken by the Fish Hawk, but Mr. Gray 
collected 4 fine specimens at San Juan. 
22. Ophiopsila fulva Lyman. 
Recorded from various parts of the West Indies in water of from 13 to 175 fathoms depth. 
Tentacle scales similar to those of the following species. There are 3 specimens of an Ophiopsila 
from station 6067 and 1 from 6080 which are apparently this species, although no one of them agrees 
perfectly with Lyman’s description. The best specimen has the disk gray, with orange spots, as in the 
type, and 4 oral papillae and 9 tooth papillae, but there are only 6 arm-spines, which are flat and 
narrow, but not acute. The other 3 specimens have 8 or 9 similar but sharper arm-spines, but the 
tooth-papillae vary from 5 to 9 and the oral papillae from 4 to 6; the upper surface of the disk is 
wanting in all. The upper-arm plates vary from square, with rounded corners, to long, narrow, and 
rounded in front. Verrill proposes to separate this species from Ophiopsila and place it as the type of 
a new genus, Amphipsila, in the family Ophiacanthidx, because of certain differences in the covering of 
the disk and the arrangement of the tooth papillae. My specimens of fulva, however, agree essentially 
in these respects with Ophiopsila riisei, and the very characteristic appearance and arrangement of 
the tentacle scales, in which the two species also agree, seem to me too important to be ignored. 
Judged by the specimens before me, Ophiopsila fulva is much more nearly allied to O. riisei than to 
Amphipsila macuhita Verrill. The latter is clearly not an Ophiopsila, and should be considered the type 
of the new genus. On this point Yerrill’s papers conflict. In his report on the Oplviuroidea of the 
Bahama expedition (Bull. Univ. Iowa, vol. 1, No. 6, Sept., 1899, p. 55) he says: “Amphipsila, gen. 
nov. Type A. fulva (Lym. ).” Then follows a characterization of the new genus which will not apply 
at all to 0. fulva Lyman. In his other paper (Tran. Conn. Acad., vol. x, pt. 2, Oct., 1899, p. 348) he 
says: “Amphipsila Verrill, 1899a, p. 55. Type A. macu lata Ver.” Then follows a copy of his original 
description of the genus, to which is added the following statement: 
“I have separated this genus from Ophiopsila, as understood by Lyman, for he included in the 
latter A. fulva (Lym.), which is closely allied to our type species.” 
This latter statement does not seem to me justifiable, as I have carefully examined Lyman’s 
original description (with which one of my specimens agrees admirably, except in the number of arm- 
spines), and it does not seem to me that fulva Lym. is at all closely allied to A. maculata Ver. 
