MUSEUM OF COMPARATIVE ZOOLOGY. 109 



Ophiomusium serratum sp. nov. 



Plate I. Fies. 23, 24, 26. 



Special Marks. — Amis rather slender and tapering, cylindrical or but 

 slightly wavy. Upper and under arm-plates persisting nearly to end of arm, 

 but no tentacles beyond third or fourth under plate. Genital opening bounded 

 by small close-set papillae. Interbrachial space between radial shields occu- 

 pied by two large plates. Papillaj along genital openings extending upward 

 as a small arm-comb. Four or five small arm-spines. 



Description of an Individual (Station 23). — Diameter of disk 10 mm. 

 Width of arm near disk, without spines, 2.5 mm. Mouth-papillae si.x on each 

 side, with one at angle of jaw, all in close contact. Mouth-shields heart or 

 rounded-diamond shape, with an angle inward ; length to breadth 1.5 : 1. 

 Side mouth-shields long triangular, extending farther out than the mouth- 

 shield ; wider without than within, where they just meet. The first four 

 under arm-plates bearing tentacle-scales are pentagonal, with an obtuse angle 

 inward, outer edge slightly curved, lateral sides re-enteringly curved ; length 

 to breadth, second arm-plate, 1. : .7. Side arm-plates thick, constricted 

 within, meeting below, even within the disk, and above beyond the second 

 upper arm-plate ; those beyond are also pentagonal, but small, broad, and 

 widely separated. Upper arm-plates triangular, with an acute angle inward, 

 and outer edge curved ; length to breadth 1 : .7. Disk covered with flat 

 plates closely soldered ; in the central space within the radial shields are six 

 rounded primary plates, separated by a circular row of small ones ; the inter- 

 brachial space is occupied by two angular plates, the outer one much larger. 

 Kadial shields long triangular, separated their entire length by one small and 

 two large scales. In the interbrachial space below are two large circular 

 plates, extending from the mouth-shield to margin of disk, on either side of 

 which are smaller circular scales. Genital scales long and very narrow, ex- 

 tending from the edge of the mouth-shield to margin of disk, on the free edge 

 of which are fine tooth-like papilla), corresponding to similar papilla) along the 

 side mouth-shields, giving a resemblance to Ophioghjpha. At the base of the arm 

 above arfi short blunt papillae on either side of first upper arm-plate. Arm- 

 spines four or five, delicate, pointed, nearly equally placed ; middle one longest 

 and nearly half as long as a side arm-plate. A single circular tentacle-scale 

 on second, third, and fourth under arm-plates, situated near the inner angle. 

 The entire surface of the animal is microscopically tuberculated. Color in 

 alcohol, white. 



Station 23, 450 fathoms, 1 specimen. 



Ophiomusium armigerum sp. nor. 



Plate I. Figs. 31, 2%. 



Special Marks. — Arms rather slender and tapering, cylindrical or but 

 slightly wavy. Upper and under ami-plates persisting nearly to end of arm, 



