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OPHIURA PANAMENSIS. 



LIST OF SPECIMENS. 



Locality. 



"Whence obtained. 



Museum of Comparative Zoology. 

 St. Thomas, W. I. I . • • 



West Indies. 

 2 I Cape Florida. 



A. H. Riise. | Alcoholii 



Univ.Miis.Cop'hagen. " 

 G. Wurdeman. Dried. 



Smithsonian Institution. 



St. Thomas, W. I. 

 St. Thomas, W. I. 

 St. Thomas, W. I. 



A. H. Riise. 

 A. H. Kiise. 

 A. H. Riise. 



Dried. 



Alcoholic, 



Dried. 



Ophiura panamensis Lyman. 



Ophioderma panameiisis Lutken; Addit. ad Hist. Oph., p. 91. 



Special Harks. — Color, in alcohol, above, greenish gray, with a cen- 

 tral light mark ; arms the same, alternating with lighter and darker 

 bands ; mouth-shields a good deal rounded ; arm-.spines stout, blunt, 

 little tapering ; side mouth-shields granulated. 



Description of a Specimen. — Diameter of disk, 25™"' ; from outer 

 side of mouth-shield to outer corner of opposite mouth-slit, 8.5"""- ; width 

 of arm without spines, 5™"' ; length of arm, 102°'"' ; distance from outer 

 side of mouth-shield to inner points of mouth-papilla% to that between 

 outer corners of mouth-slits, 4.3 : 4.6. Mouth-papilla?, nineteen or twenty 

 to each angle of mouth ; outermost one long and spine-like, reaching 

 above its next neighbors ; the next one, or two, flat and squarish ; the 

 rest fine and spiniform, except the innermost, which is much larger and 

 stouter. Teeth five, upper and under ones flat and pointed ; the others 

 flat, squarish, with a curved cutting edge ; they are unusually short. 

 Mouth-shields broader than long, irregular oval, -with a rounded angle 

 within ; length to breadth, 2.2 : 3. Under arm-plates octagonal, with 

 rounded corners ; about as broad as long ; a Httle overlapj)ing ; length 

 to breadth (twelfth plate), 1.4 : 1.5. Upper arm-plates much broader 

 than long, overlaj)ping ; outer side nearly straight, with a slight re- 

 entering curve in the middle ; lateral sides well rounded ; length to 

 breadth (ninth plate), 1.4 : 4 ; three or four plates inclosed by the incis- 

 ions in the disk. Disk, above and below, finely and closely granulated, 

 except on radial-shields, and some narrow lines of scales at base of arm, 

 which run under the disk as far as the inner end of the outer genital 

 slit ; about 120 grains to a square mm. Radial shields oval ; length to 



