CRINOIDEA AND ECHINOIDEA 



7 



Nema^ter iowensis 



Actinometra iowensis Springer, 1902, Amer. GeoL, 30, p. 98, 1903, Bull. 



Lab. Nat. Hist., Univ. Iowa, 5, p. 217; pi. 1. 

 Nemaster iowensis A. H. Clark, 1910. Ann. Mag. Nat. Hist. (8), 5 p. 361. 



Certainly, among the echinoderms taken by the Bahama 

 Expedition, no species is so remarkable as this. Collected in 

 shallow water at the Tortugas, the specimens were at once 

 recognized by Professor Nutting as of very unusual interest, 

 and in the ''Narrative" (pp. 129-130) he speaks of them as 

 follows : ' ' Perhaps the greatest surprise was when we found 

 a magnificent crinoid with a spread of about twelve inches 

 growing in water less than three feet deep. These specimens 

 were of a rich golden-brown color, which has not faded in alcohol, 

 and belonged to the genus Actinometra. The mouth is even 

 more excentric tjian usual in this genus and the pinnules are 

 long and slender. The arms appear to be more brittle than in 

 other crinoids and the ultimate ramifications are twenty-four 

 in number. This is probably the handsomest species of free 

 crinoid secured during the cruise, and the unexpectedness of 

 the discovery added to its interest." 



The structural peculiarities of the species have been fully 

 discussed and figured by Springer, and it is not necessary for 

 me to enter into them. But it may be worth while to add a 

 few words in regard to the subsequent history of this notable 

 comatulid. Professor Nutting says in a footnote (p. 130) that 

 Mr. Agassiz told him he had found large comatul^ in shallow 

 water at the Tortugas. It is greatly to be regretted that no 

 such comatulids are in the M. C. Z. collection. It is possible 

 they were sent to Hartlaub many years ago with most of the 

 M. C, Z. comatulids. If so they are still missing, as that em- 

 inent German scientist never returned to the Cambridge Mu- 

 seum any of its collection, save a full series of Comactinia echin- 

 o'ptera. All else, he reported, as hopelessly lost! 



Since the establishment of the Marine Laboratory of the 

 Carnegie Institution at the Tortugas in 1904, Dr. Mayer has 

 made a constant effort to rediscover Nemaster ioivensis, but 

 without finding a single specimen. The present writer spent 

 the month of June, 1917, at the Tortugas and at everj^ oppor- 



