NO. 3 BURGESS SHALE FOSSILS WALCOTT 9 



posterior part of the body is broken off. The anterior pointed end of 

 the head is broken off in such a manner that the presence of a frontal 

 appendage is suggested. The large opening on the side of the head 

 indicates a large pedunculated eye comparable with that of Opabiiiia 

 regalis (pi. 28, fig. i). 



'' Appendages. — Of the head appendages, the antennae are the best 

 preserved. These are large and composed of several strong joints, 

 of which three now show from beneath the carapace ; the second of 

 these bears a long slender branch on its inner margin, and the third 

 two branches, one of which is similar to that of the second joint. 

 These two branches appear to be composed of one very long slender 

 joint followed at the end by several short small joints that curve 

 upward and presumably gave the branches flexible extremities ; the 

 third and lower branch has a similar slender proximal joint that at 

 its outer end has three slender, jointed branches. This structure makes 

 a very effective clasper of each of the antennae. Back of the right 

 antennae are two narrow appendages that may be the ends of one of 

 the third and fourth pairs of head appendages. 



" The thoracic legs terminate in flat, elongate, broad, lanceolate 

 joints. The terminal joint is about three-fifths the entire length of 

 the leg, and has a fringe of strong setae on its outer and posterior 

 margin. The condition of preservation is such that the details of struc- 

 ture of the other portions of the leg cannot clearly be determined." 



The illustrations presented herewith apparently were prepared by Doctor 

 Walcott to exhibit the detailed structure of this interesting crustacean. 



Plcsiotypes.—U. S. N. M.. Nos. 83943a-g. 



LEANCHOILIA MAJOR, new species 



Plate 13, fig. 3 



Several specimens, of which the best is illustrated, were labeled LeanchoUia 

 major by Walcott. Just why he should have chosen this specific name is not 

 readily apparent as these individuals are not sufficiently larger than L. superlata 

 to warrant the designation. In fact there is but little difference between this 

 form, which happens to be flattened out horizontally, and the specimen shown 

 in figure 2, plate 13, referred to the genotype. 



Holotypc.—V. S. N. M., No. 83944. 



NARAOIA Walcott 1912 



NARAOIA COMPACTA Walcott 



Plate 13, fig. 4; plate 14, figs. 1-3; plate 15, figs. 2-3 



Naraoia compacta Walcott, 1912, Smithsonian Misc. Coll., vol. 57, no. 6, p. 175, 

 pi. 28, figs. 3, 4. 



Many specimens of this interesting form have been found since its 

 preliminary description in 1912, but none shows the cephalic ap- 



