1915. J NATURAL SCIENCES OF PHILADELPHIA. 87 



entire, or double with soldered halves, and always lack a third, 

 median secondary plate. Further, the peristomal plates of the 

 former type are distinctly longer in proportion to their width than 

 are those of the latter. 



Ignoring the smaller size, Ophiurocfueta much resembles Ophi- 

 arachna, the only essential differences being the presence of scattered 

 disk spines and the absence of accessory oral shields. The systematic 

 value of the accessory oral shields is, however, considered insignificant 

 by Dr. H. L. Clark. I have also observed the absence of the acces- 

 sory oral shields in some interradii of a specimen of Ophiarachna 

 incrassata. One may safely say, then, that the relation of Ophiu- 

 rochceta to Ophiarachna is parallel to that of Ophiomastiz to Ophio- 

 coma or of Ophiochceta to Pectinura. 



Subfamily 2. OPHIODERMATIN.E nov. 



(Characters as given in key, p. 83.) 



This subfamily includes Ophioconis, restr., Cryptopelta, Bathy- 

 pedinura, Pectinura, Ophiopezella, Ophiochceta, Ophiarachnella, Ophio- 

 chasma, Ophioderma, Ophioncus and Diopederma. 

 Bathypectinura gotoi sp. nov. 



Diameter of disk 50 mm. Length of arms 195 mm. Width of 

 arms at base 7 mm. Disk pentagonal, flat, closely covered with 

 fine granules, of which four or five are contained in 1 mm. Radial 

 shields only partly naked, but distinguishal^le through the super- 

 ficial granulations, by the slight swelling, as large, elongated ovate 

 plates, nearly half as long as disk radius, wider outwards; naked 

 part very small, ovate, and wider without than within. Genital 

 slits very long, almost reaching disk margin. Genital plates visible 

 from exterior, lying along adradial border of slits, long, very stout. 



Oral shields small, triangular, with rounded angles and convex 

 sides, nearly as wide as long. Accessory oral shields very rudiment- 

 ary; in one of the two specimens they are absent, but in the 

 other they are indistinctly represented by one or two small scales, 

 which are separated from the oral shield by granules. The adoral 

 shields are almost, and the oral plates entirely, covered with granules, 

 which are coarser and sparser than distally. Eight or nine oral 

 papillse on either side; outermost two or three large, flat, thin, outer 

 second largest; inner ones small, more or less conical, obtuse. Five 

 to seven teeth, irregular in shape and size, with pointed or rounded 

 ends, arranged in an irregular vertical row. 



Arms long, stout, gradually tapered outwards, with a rather sharp 



