Vol. 32, pp. 245-246 December 31, 1919 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



A NEW AMPHIPOD PARASITIC ON A CRINOID.^ 

 BY CLARENCE R. SHOEMAKER. 



Several male specimens of this Amphipod were discovered by 

 Mr. Austin H. Clark imbedded in the discs of the Crinoid Iri- 

 dometra melpomene taken by the "Albatross" in the China Sea 

 at a depth of 100 fathoms. In general appearance they closely 

 resemble G. 0. Sars' species Laphystiopsis planifrons taken off 

 the coast of Norway; but upon closer examination several differ- 

 ences are to be observed. 



Family LAPHYSTIOPSIDAE. 

 Laphystiopsis iridometrae, new species. 



Preliminary description. — Eyes (in the alcoholic specimens) without pig- 

 ment and consisting of a few visual elements under the surface of the con- 

 vex sides of the head. First and second antennae not differing much in 

 length, first with 12 segments in the flagellum and the second with 10 Per- 

 aeopods proportionately shorter and stouter than in L. planifrons and no 

 spines on the fifth and sixth segments of the fifth peraeopods. The first 

 four pairs of side-plates produced conspicuously forward. The first three 

 abdominal segments each with a low, blunt, dorsal keel. Fourth abdominal 

 segment without dorsal keel. Telson less oval and more heart-shaped than 

 in L. planifrons and in the normal position extends back to about one-third 

 the length of the rami of the third uropods. 



Length. — 5 mm. 



Locality. — China Sea, Albatross Station No. 5310, depth 100 fathoms. 



Type.— Cat. No. 49599, U. S. N. M. 



'Published by permission of the Secretary of the Smithsonian Institution. 

 51— Proc. Biol. Soc. Wash., Vol. 32, 1919. (245) 



