A TAXONOMIC STUDY ON PYKOSOMA — METCALF AND HOPKINS. 255 



Occurrence and distribution. This is the commonest Pyrosoma 

 in the Atlantic Ocean. It seems to be the only one thus far 

 reported from the Mediterranean Sea. The Challenger took speci- 

 mens in the Antarctic Ocean, south of Australia, in latitude 47° 25' S. 

 From the Antartic Ocean it would be easy for this form to be carried 

 into the Indian and Pacific Oceans. In the Indian Ocean its occur- 

 rence has been pretty well established, but reports of P. ailanticum 

 giganteum occurring in the Pacific are not so clear. The published 

 descriptions of Pacific forms which could be classed in the ailanticum 

 group apply only to what we have been calling the subspecies 

 ailanticum. 



Specimens of P. ailanticum. giganteum in the United States National 

 Museum collection are as follows: 



Taken by the Albatross on the east coast of North America at 

 station — 



D. 2088, south of Marthas Vineyard, Sept. 20, 1883; 143 fathoms;, 

 surface temperature 68° F.; one specimen, Cat. No. 200 U.S.N.M. 



D. 2089, south of Marthas Vineyard; Sept. 20, 1883; 168 fathoms; 

 surface temperature 69° F.; one specimen, Cat. No. 6402 U.S.N.M. 



D. 2091, south of Block Island; Sept. 21, 1883; 117 fathoms; sur- 

 face temperature, 69 ° F. ; one specimen, Cat. No. 6487 U.S.N.M. 



D. 2094, south of Block Island; Sept. 21, 1883; 1,022 fathoms; 

 surface temperature 68° F.; one specimen. 



D. 2171, off Maryland, July 20, 1884; 444 fathoms; surface tem- 

 perature 75° F. ; one specimen. 



D. 2381, off New Orleans, Gulf of Mexico; March 2, 1885; 1,330 

 fathoms; surface temperature 69° F.; one specimen, Cat. No. 428, 

 U.S.N.M. 



D. 2642, Straits of Florida; April 9, 1886; 217 fathoms; surface 

 temperature 74° F.; two specimens, Cat. No. 790, U.S.N.M. 



D. 2655, north of Great Bahama Island ; May 2, 1886; 338 fathoms; 

 surface temperature 76° F.; one specimen, Cat. No. 791 U.S.N.M. 



D. 2668, off Fernandina, Florida; May 5, 1886; 294 fathoms; surface 

 temperature 76° F.; one specimen, Cat. No. 792, U.S.N.M. 



D. 2674, off Charleston, South Carolina; May 6, 1886; 316 fathoms; 

 surface temperature 76° F.; one specimen, Cat. No. 799 U.S.N.M. 



D. 2714, off Cape Henry; Sept. 17, 1886; 1,825 fathoms; one speci- 

 men, Cat. No. 874 U.S.N.M. 



An unnumbered station south of Block Island (240 miles east of 

 Cape Cod); one specimen, Cat. No. 6405, U.S.N.M. 



Taken by the Fish Hawk, while dredging in Gulf Stream, during the 

 year 1903: 



Sta. 7518, off Cape Florida; March 30, 1903; 156 fathoms; surface 

 density 1.024; one specimen, Cat. No. 6510, U.S.N.M. 



Sta. 7519, off Cape Florida; March 30, 1903; 186 fathoms; surface 

 density, 1.024; one specimen, Cat No. 6498 U.S.N.M. 



