72 BULLETIN 84, UNITED STATES NATIONAL MUSEUM. 



Family OPHIOMYCETID^}. 



OPHIOMYCES MIRABILIS Lyman. 



Plate 3, fig. 6. 



Ophiomyces mirabilis LYMAN (69), p. 342. 

 Ophiomyces mirabilis LJUNGMAN (71), p. 652. 

 Ophiomyces mirabilis LYMAN (82), p. 242. 

 Ophiomyces mirabilis LYMAN (83), p. 270. 

 Ophiomyces mirabilis KCEHLER (07), p. 316. 



Albatross station 2644. Apr. 3, 1886. Lat. 25 40' N.; long. 80 00' W.; 193 

 fathoms; gy. s.; temp. 43.4 F. Two specimens. 



EisTi Hawk station 7286. Feb. 19, 1902. Lat. 24 18' N.; long. 81 47' 

 45" W.; 133 fathoms; s.; temp. 53.5 F. One specimen. 



Fish Hawk station 7296. Feb. 26, 1902. Lat. 24 21' 25" N.; long. 81 47' 

 45" W.; 122 fathoms; co.; temp. 54 F. Two specimens. 



Lyman gave a very good description of 0. mirabilis but he did not illustrate it. 

 The example from station 2644 is of rather large size but the upper face is entirely 

 missing; I was able to bring the arms down to the same level and to take a photo- 

 graph of the under face which I reproduce here (pi. 3, fig. 6). 



Family OPHIACANTHID^. 



The collection of Ophiurans which was sent me by the United States National 

 Museum included a fairly large number of Ophiacanthidse, some of which are new, 

 while the others belong to species already known. Owing to the special difficulties 

 which are experienced when making determinations in that family, I devoted 

 myself not only to describing the former, but also, and with special attention, to 

 the study of the known forms regarding which our knowledge is incomplete. Several 

 species of the Ophiacanthidse of the American coasts were named long ago by 

 Verrill, but most of them were described by him in such a summary way that 

 specialists agree that it is impossible to identify these species, the more so as they 

 have not been illustrated. I have found in the collection of the National Museum 

 a few of these species, and I have been able to obtain the cotypes of some others, 

 but unfortunately I have been unable to borrow all the species which I should like 

 to have studied. I have also examined with great benefit a few specimens deter- 

 mined by Liitken or by Ljungman which were most kindly lent me either by Pro- 

 fessor The'el, of Stockholm, or by my friend Doctor Mortensen, of Copenhagen. 

 Thanks to these various specimens, I have been able either to ascertain some doubt- 

 ful determinations or to establish some comparisons, or again to complete, with full 

 knowledge of the question, some insufficient descriptions. My researches would have 

 been more complete had I been able to examine a few Atlantic forms such as 

 Ojjhiacantha cuspidata Lyman, segesta Lyman, and varispina Verrill, the affinities 

 of which I consider as being somewhat doubtful. 



Before beginning with the description of the Ophiacanthidse, I must admit 

 that I feel somewhat puzzled, aa will be understood by those who have studied the 

 Ophiurans. The classification of the Ophiacanthidaa now represents an actual chaos, 

 and the very limits of that family can not be indicated in a sufficiently precise 



