84 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



OPHIOTRETA VALENCIENNESI (Lyman). 



Plate 16, fig. 4; plate 93, fig. 6. 



See for bibliography : 



Ophiacantha valenciennesi Kcehlek ('04), p. 110; ('07), p. 292; ('09), p. 



188.— H. L. Clark ('15), p. 205. 

 Ophiacantha (Ophiotreta) valenciennesi Kcehlee ('14), p. 102. 



Locality. — Albatross station 5306; China Sea, in the vicinity of 

 Hongkong (lat. 20° 55' 00" N., long. 116° 40' 00" E.) ; 311 meters 

 (170 fathoms) ; October 26, 1908; co., S. 



One specimen (Cat. No. 41151, U.S.N.M.). 



Notes. — The single specimen is in rather poor condition ; the arms 

 are broken into many fragments, and the dorsal surface of the disk 

 has been almost completely torn away. 



Verrill placed O. valenciennesi in his subgenus Ophiotreta, with 

 O, sertata and O. lineolata; H. L. Clark retained in this subgenus 

 O. sertata and O. lineolata, to which he added O. eximia, O. gratiosa, 

 and O. sociabilis, but he placed O. valenciennesi in the genus Ophia- 

 cantha ('15, p. 205). I shall follow Verrill's example in placing O. 

 valenciennesi in the genus Ophiotreta; it must be recognized, how- 

 ever, that it differs notably from the other species assigned to this 

 genus in having the tentacle scales doubled throughout the length 

 of the arms. But I do not believe that there is any present necessity 

 for placing O. valenciennesi in a distinct genus. 



The granules on the dorsal surface of the disk are continued onto 

 the two or three first upper arm plates, but I notice that some of the 

 plates which follow, to the number of five or six, or sometimes even 

 less, show in the middle of their distal edge a single rounded granule 

 a little longer than broad, narrower than the granules of the dorsal 

 surface of the disk, and slightly rugose; the following plates lack 

 these granules. These must be very deciduous, and I have not seen 

 them on the various individuals of O. valenciennesi which I have 

 examined up to the present time ; however, in reexamining the speci- 

 mens collected by the Travailleur and the Talisman I have been able 

 to find two on one of the specimens. 



The granules on the dorsal surface of the disk, as likewise those 

 which are sometimes found on the free edges of the upper arm plates, 

 are not perfectly rounded ; isolated and viewed under the microscope 

 they are seen to be very short cylinders inserted by a broadened and 

 flat base, almost as high as broad, and ending in a strongly convex 

 surface furnished with short and conical teeth, which may be con- 

 tinued down the sides of the granule (pi. 93, fig. 6). 



I have already had occasion at different times to speak of this 

 species and of its enormous geographical range. 



