MUSEUM OF COMPARATIVE ZOOLOGY. 219 



short, squarish, close-set mouth-papillaj on each side of an angle, with 

 one spearhead-shaped at the apex. Mouth-shield flat, of a rounded heart- 

 shape, with a small peak within, and a curve without ; length to breadth 

 3 : 2.7 mm. Side mouth-shields small, much wider without than within, 

 where they just meet. First under arm-plate small and rounded ; the next 

 three are as wide as long, with outer side curved and much wider than the 

 inner, which is an obtuse angle ; lateral sides re-enteringly curved opposite 

 the tentacle- pores. The rudimerary plates beyond have a rounded triangular 

 shape. Side arm-plates large, not swollen, meeting broadly below and above 

 beyond the third upper arm-plate. First two upper arm-plates quadrangular, 

 with inner angle truncated ; beyond, they are diamond-shaped. Disk flat 

 and five-sided, covered with large radial shields and thin plates and scales. 

 The central primary plate, which is much smaller than the other five, is sepa- 

 rated from them by numerous fine scales. Radial shields long triangular, 

 slightly swollen, minutely tuberculated, having a rounded angle within, and 

 outer edge curved ; separated their entire length by irregular rows of minute 

 scales ; length to breadth 6.2 : 3. Interbrachial spaces above and below also 

 filled by rows of scales, whereof one larger stands on the margin of the disk. 

 Genital openings reaching about two thirds the distance to the margin, bounded 

 on both alges by ten or more very small, rounded, closely soldered papillae. 

 Three minute arm-spines. A small tentacle-scale on either side of each pore. 

 Color in alcohol, pale straw. 



Station 29, 955 fathoms, 3 specimens. 



This species stands next 0. arclmster, from which it is distinguished by the 

 covering of the disk. 



Ophiomusium testudo Ltm. 



Ophiomusium testudo, 111. Cat. Mus. Comp. Zool. Vol. VIII. Pt. II. p. 8, PI. I. 

 Figs. 6-8. 1875. 



Sigsbee, off Havana, 177 fathoms, 3 specimens (var. ?). Sigsbee, off Havana, 

 80 fathoms, 1 specimen. Station 45, 101 fathoms, 9 specimens. 



Ophiomusium validum Ljk. 

 Oj^Momusixim validum, Of. Kong. Akad. Dr. Goiis Oph. p. 618. 1871. 

 Station 2, 800 fathoms, 1 specimen. Station 16, 292 fathoms, 1 specimen. 

 Station 29, 968 fathoms, 9 specimens. Station 33, 1568 fathoms, 1 specimen. 

 Station 41, 860 fathoms, 1 specimen. 



These are identified by the original sent me from Stockholm through the 

 courtesy of Prof. Loven. 



Ophiomusium acuferum Lym. 



Ophiomusium acuferum, 111. Catal. Mus. Comp. Zool. No. 8. Pt. II. p. 7, PI. I. 

 Figs. 1-5. 1875. 



Station 20, 220 fathoms, 1 specimen. Station 32, 95 fathoms, 5 specimens. 



