PAKT 5 A MONOGRAPH OF THE EXISTING CRINOIDS 413 



authority of P. H. Carpenter in 1877 and 1881, the misapplication of the name being 

 pointed out by Carpenter in the latter year. 



In his work upon the marine invertebrates of New England, the Maritime Provinces 

 of Canada, and Newfoundland, Prof. Addison E. Verrill was struck by the small size 

 and generally undeveloped aspect of the individuals of this species from this region as 

 compared with the magnificent large and robust specimens from Greenland, with which 

 he was familiar in the Peabody Museum at Yale University and in the Museum of 

 Comparative Zoology at Harvard. He designated this depauperate form as Antedon 

 eschrichtii var. acadiae, which name appears as a nomen nudum in a checklist of the 

 marine invertebrates of this coast published in 1879, but there is no further reference 

 to it. 



Prof. F. Jeffrey Bell in 1882 described under the name of Antedon eschrichti var. 

 magellanica [= Florometra magellanica] what he considered to be a variety of this species 

 from the Alert collections. 



In 1884 P. H. Carpenter described as Antedon quadrata some small specimens 

 which had been dredged by the Porcupine in the Faroe Channel those which had been 

 mentioned by Wyville Thomson under the name celticus. This name quadrata has 

 been widely used for a number of undersized and undeveloped varieties of this species, 

 including the one covered by VerriU's name acadiae, published five years previously but 

 never diagnosed, as well as for young individuals in various stages. 



Through the study of the material in the Challenger and Blake collections P. H. 

 Carpenter had learned the great importance from the systematic standpoint of the 

 development of side and covering plates along the ambulacra as seen in the Calomet- 

 ridae, Thalassometridae and Charitornetridae. Finding comparable plates well-devel- 

 oped in certain specimens from near Vard0, he described them in 1886 as a remarkable 

 new species, which he called Antedon barentsi. That this in reality is only a minor 

 variety of H. glacialis was later shown by Mortensen (1903), Grieg (1904) and Doderlein 

 (1905). 



In 1907 the present author described under the name Antedon arctica a small dis- 

 colored specimen from Cape Sabine, and a few months later proposed the genus 

 Heliometra with Alecto eschrichtii J. Muller, 1841, as the type. In the following year 

 he described Heliometra juvenalis from off Cape Kaper, Baffin Land (from the Esqui- 

 maux collection), and in the same year adopted the specific name glacialis in place of 

 eschrichtii, a change to which exception was taken by Prof, von Hofsten and by Dr. 

 H. L. Clark. However, following issue with Mortensen and Koehler, the name glaci- 

 alis has now been generally adopted. 



Remarks. Thanks to its very general occurrence within its range, its great size, 

 conspicuous color and beautiful form, and to the remoteness of its habitat, interest in 

 it not being inhibited by familiarity, this is in many respects the best known of all the 

 crinoids. The major features of its geographical, bathymetrical, and thermal distribu- 

 tion are known in greater detail and with greater exactness than those of any other 

 species. 



But its embryology and early stages still remain to be studied, and its pentacrinoid 

 stage has only been described from a few specimens, all in the later phases of develop- 

 ment. 



Its occurrence, like many echinoderms and other fixed or sedentary marine animals, 

 in aggregations of which all the individuals are of a similar size and sometimes show 



