No, 12. — Reports on the scientific results of the Expedition to the Tropical 

 Pacific in charge of Alexander Agassiz, on the U. S. Fish Com- 

 mission Steamer Albatross, from Augiist, 1899, to March, 1900, 

 Commander Jefferson F. Moser, U. S. N., Commanding. 



XVIII. 



Reports on the scientific results of the Expedition to the EaMern Tropical 

 Pacific in charge of Alexander Agassiz, by the U. S. Fish Com- 

 mission Steamer Albatross from October, 1904, ^o March, 1905, 

 Lieut. Commander L. M. Garrett, U. S. N., Commanding. 



XXX. 



Ophiuroidea. 



By Hubert Lyman Clark. 



The number of ophiurans collected by the Albatross on her 

 Tropical Pacific expeditions was not large and it has seemed best to 

 make a single report on the two collections. They were originally 

 sent to Professor Ludwig at Bonn, but he had made only a preliminary 

 examination when his untimely death cut short his i-esearches. There 

 are in all about 550 specimens, representing 50 species. Of these 168 

 specimens of 20 species were taken during the cruise of 1899-1900, 

 and 381 specimens of 33 species were collected in 1904-05. There are 

 also included a very few specimens taken by the Albatross in 1891, 

 which \vA\e never yet been placed on record. Onl;^- 7 species are new 

 to science and one third of the remainder are common shallow-water 

 species of Pacific reefs and shores. 



Ophiomyxidae. 



Ophiogeron edentulus. 



Lyman, 1878. lUill. M. C. Z., 5, p. ItJl. 1882. ChaUenger Oph., pi. 12, fig.. 

 16-18. 



A single .specimen, with the disk-covering torn away, measures 

 5 mm. across the disk and has arms 18-20 mm. long. It is someAvhat 



