80 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



too much contracted to show the lobes. Though preserved in forma- 

 lin, the test is tough and cartilagenous, rather thick, with numerous 

 fine sharply defined wrinkles on the surface, becoming especially 

 rough about the apertures. Color (retained even a long time after 

 transferring to alcohol) bright crimson on the exposed surface; more 

 or less of the red color pervades also the substance of the test but not 

 the mantle or internal organs. Size 22 mm. long, 19 mm. wide, and 

 15 mm. in extreme dorso-ventral diameter. Apertures 10 mm. apart. 

 The other specimen evidently grew on some slender object, per- 

 haps a branch of an alcyonarian, and though also attached by the 

 whole length of the ventral surface, the body is more cylindrical, and 

 the apertures are nearer together, the branchial aperture being ter- 

 minal and in this case clearly 4-lobed. The surface is smoother than 



in the first specimen, 

 and the test white, 

 only slightly tinged 

 with red. The size is 

 slightly larger (26 mm. 

 long). 



The following de- 

 scription of the anat- 

 omy is based on the 

 first-mentioned speci- 

 men, the other being in 

 poor condition inter- 

 nally and not having 

 the gonads developed. 



Mantle muscles well 

 developed, strongest on 

 the dorsal region and right side. Narrow but numerous and very 

 closely placed bands radiate from the bases of the siphons and ex- 

 tend far down on the sides of the body. They are overlaid by closely 

 placed circular bands on the dorsal region. Ventrally the muscula- 

 ture becomes thinner and more diffuse, narrow groups of fibers cross- 

 ing each other in various directions. 



For some reason not clearly apparent the tentacles were in a poor 

 state of preservation. Apparently they are scantily branched, though 

 provided with very broad membranes. 



Dorsal tubercle rather large, but not prominent, its orifice crescent- 

 shaped with the horns strongly turned in and the concavity forward. 

 (In the other specimen the orifice forms nearly a circle, the short 

 open interval being forward. One horn only is strongly bent 

 inward.) 



Dorsal lamina broken up into a series of moderately long, closely 

 placed languets. 



Figs. 20-29. — Pyura duplicata, new sfecies. 20, 

 Left and right sides of body, x 1.5. 27, Dorsal 

 tubercle and part of dorsal lamina. x 10. 



28, Dorsal tubrrcle of another individual. X 10. 



29, Part of gonad. X 5. 



