ASTEROIDEA 165 



Hemicia obesa Fisher, 1906, p. 1091. 



Henricia hyadesi Clark, H. L., 1910, p. 336, pi. 2, fig. 5. 



Hemicia pageiistecheri Koehler, pars, 1923, p. 60. 



St. WS 81. 8 miles north-west of North Island, West Falkland Island, 81-82 m., sand, 6 speci- 

 mens. 



St. WS 84. yi miles south-west of Sea Lion Island, East Falkland Island, 75-74 m., coarse sand, 

 shell, stones, 8 specimens. 



St. WS 85. Falkland Islands, 52° 09' S, 58° 14' W, 79 m., sand and shell, 11 specimens. 



St. WS 86. Falkland Islands, 53° S3' 30" S, 60° 34' 30" W, i5i-i47m., sand, shell, stones, 19 

 specimens. 



St. WS 93. West Falkland Island, 51° 51' S, 61° 30' W, 133-130 m., grey sand, 3 specimens. 



St. WS 108. Falkland Island, 48=" 30' 45" S, 63° 33' 45" W, 1 18-120 m., fine dark sand, i speci- 

 men. 



St. WS 109. Falkland Islands, 50° 18' 48" S, 58° 28' 30" W, 145 m., fine dark sand, i specimen. 



St. WS 220. South-east of Cape Tres Puntas, 47° 56' S, 62° 38' W, 108-104 ™-' i specimen. 



St. WS 243. North-east of Falkland Island, 51° 06' S, 64° 30' W, 144-141 m., coarse dark sand, 

 13 specimens. 



St. WS 248. Falkland Island, 52° 40' S, 58° 30' W, 210-242 m., fine green sand, pebbles, shells, 

 4 specimens. 



St. WS 576. Berkeley Sound, 51° 35' S, 57° 49I' W, 34-24 m., i specimen. 



St. WS 776. Off Cape Tres Puntas, Argentina, 107-99 "!•' 2 specimens. 



St. WS 782A. North Falkland Island, 50° 29!' S, 58° 23I' W, 141-146 m., i specimen. 



St. WS 791. North-east of Cape Tres Puntas, 45° 38' S, 62° 57' W, 97-96 m., i specimen. 



St. WS 796B. South-east of Cape Tres Puntas, 47° 53^' S, 63° 32!' W, 108-112 m., i specimen. 



St. WS S04. North-west of West Island, Falkland Islands, 150-143 m., i specimen. 



St. WS 807. East of Porto Santa Cruz, 49° 50!' S, 65° 03' W, 125-126 m., i specimen. 



This species differs from H. stiideri (Perrier) in having a rather large-meshed abactinal 

 skeleton — a characteristic which is illustrated by Sladen's and Perrier's figures. The 

 actinal skeleton is also more open, with larger meshes and smaller plates. In both 

 species 3 longitudinal, regular series of plates are usually present, representing i actinal 

 (contiguous with adambulacrals) and 2 marginal series. The actinal series extends to 

 about the middle of ray, and in robust specimens of obesa, a second, shorter actinal series 

 is present exterior to the first. As a matter of fact this second series is present also in 

 slenderer rayed specimens (similar to the type of hyadesi) but the skeletal spaces are 

 smaller. Similarly, 1-3 short longiseries of intermarginal plates are present at base of 

 ray, the length of series and spacing varying with robustness of ray. 



There are about 6-9 subambulacral spines, usually arranged with i , sometimes 2, on 

 the furrow margin (above the curved, generic, furrow spinelet), followed by 2 not very 

 regular trans-series of 3 or 4 spines each ; or the innermost spine is followed by i or 2 

 similar but slightly shorter ones, and then a group of 3-6 spinelets. There is considerable 

 variation in arrangement but the spinelets are fewer in number than in H. stiideri. In 

 very small specimens occasionally plates carry a single transverse series of 5 or 6 

 spinelets after the manner oi pagenstecheri (q.v.). 



It hardly seems useful to divide this species into named formae such as forma obesa 

 and forma hyadesi, on account of the large number of intermediate variations not quite 

 typical of either. One variant (e.g. from Sts, WS 248 and 782 a) does not show a clear 



DXX 13 



