The Gephyrea collected by the Canadian Arctic 

 Expedition, 1913-18. 



By Ralph V. Chamberlin 



Museum of Comparative Zoology, Cambridge, Mass. 



The collection embraces but four specimens of the Gephyrea, these having 

 been taken from the stomachs of fish at two widely separated stations. All 

 belong to one species, the widespread northern Priapulus humanus (Linn^). 

 In addition some other Gephyreans were received for study from the Geological 

 Survey, and notes upon these are here included. They represent six species, 

 the Priapulus mentioned above, and five Sipunculids, — Physcosoma agassizi 

 (Keferstein), Physcosoma japonicum (Grube), Phascolion strombi (Montagu), 

 a previously undescribed Phascolosoma, and Phascolosoma eremita (Sars). 



PRIAPULIDAE. 

 Priapulus humanus (Linn6). 



1758. Priapus humanus Linn£. Syst. Nat., ed. 10, p. 656. 

 1766. Holothuria priapus LinniS. Syst. Nat., ed. 12, p. 1901. 

 1816. Priapulus caudatus Lamarck. Hist. Nat. Anim. sans Vert^b, p. 77. 

 1845. Priapulus hibernicus McCoy. Ann. Mag. Nat. Hist., ser. 1, 15, 

 p. 272. 



Two specimens were taken from the stomach of a nine and a half inch long 

 female Gymnocanthus pistilliger Gill at Bernard harbour. Northwest Terri- 

 tories, June 14, 1916, at Station 49/. The larger of these is 6 centimeters long, 

 inclusive of the fully protruded proboscis and exclusive of the branchial fila- 

 ments, with a diameter of 1 • 1 centimeters. The second specimen is only about 

 1 • 8 centimeters long. Two other small specimens were taken from a Pleuro- 

 nectes stellatus Pall, at Grantley harbour, Alaska, July 31, 1913 (Station 20 d). 

 Besides the specimens secured by the Canadian Arctic Expedition there is in 

 the collection a fine specimen, 10 centimeters long, taken on the beach of Hudson 

 bay at Fort Churchill, Keewatin, by James M. Macoun, October, 1910. 



SIPUNCULIDAE. 



Phascolosoma hudsonianum, n. sp. 



Type specimen. — Catalogue No. 101, Victoria Memorial Museum, Ottawa. 

 One specimen. 



Body proper, i.e., from the anus caudad, slenderly subpyriform, with a 

 conspicuous pointed caudal appendage abruptly set off, anteriorly uniform in 

 width with the proboscis. In the type the length to the tip of caudal appendage 

 is 3-4 times the greatest width. Body about one and a half times the length of 

 the proboscis. Body light brown, in gen^eral appearing shining and of a some- 

 what pearly lustre; but papillae are visible upon close inspection even with the 

 naked eye over the entire surface, the papillae obviously densest at caudal end and 

 over the narrow appendage and near level of and just in front of the anus where 

 also the skin is more obviously reticulate; skin more strongly rugose on caudal 

 surface. Papillae subconic with base broad. No hooks present on the pro- 



3d 



