692 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



BATHYMETRA CARPENTERI A. H. Clark 



FIGURE 42 



Antedon abyssicola (part) P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, ISSS^p. 

 191 (description, in part; Challenger sta. 160), pi. 33, fig. 2; similarly included under the same 

 name by subsequent authors. 



Bathymetra carpenteri A. H. CLARK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 132 (listed; nomen 

 nudum); Proc. U.S. Nat. Mus., vol. 34, 1908, p. 235 (Antedon abyssicola P. H. Carpenter, 1888, 

 specimen from Challenger sta. 160, shown on pi. 33, fig. 2; characters); Mem. Australian Mus., 

 vol. 4, 1911, p. 796 (Challenger, SW. of Melbourne, 2600 fms.); Crinoids of the Indian Ocean, 

 1912, p. 33 (=Antedon abyssicola P. H. Carpenter, 1888, in part), p. 245 (synonymy; west of 

 Tasmania, 2600 fms.); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 66 (published references 

 to the specimen in the B.M.; Challenger sta. 160) ; Journ. Washington Acad. Sci., vol. 5, 1915, No. 

 3, p. 81 (Antarctic; range) ; Die Crinoiden der Antarktis, 1915, p. 106 (collected by the Challenger; 

 recorded as Antedon abyssicola), p. 107 (in key to Antarctic crinoids), p. 147 (synonymy; range), 

 p. 170 (a deep water Antarctic species), p. 171 (systematic and geographical relationships); 

 Unstalked crinoids of the Siboga-Exped., 1918, p. 254 (in key; range; references). GISLEN, 

 Ark. Zool., vol. 19, No. 32, 1928, p. 11 (note); Rep. Swedish Deep Sea Exped., vol. 2, Zool., 

 No. 4, 1951, p. 56 (depth range). 



Diagnostic Jeatures. The centrodorsal has a flattened dorsal pole with the cirrus 

 sockets alternating irregularly around the sides, some close to the base; the radials 

 are aligned at a distinct angle with the base of the centrodorsal in side view; the brachial 

 articulations are hollowed out dorsally to an unusual extent; the cirri and pinnules 

 are unknown. 



Description [by A.M.C.]. The holotype and only known specimen is small. The 

 arms are all broken but were probably less than 20 mm. in length. From the proximal 

 edge of the IBri to the second syzygy measures 6.0 mm. and the width at the first 

 syzygy is 0.55 mm. 



The centrodorsal is low hemispherical with the dorsal pole raised but truncated 

 into a broadly flattened apex. There are 10 cirrus sockets arranged in a zigzag row 

 around the sides except for one which is placed almost directly above another. They 

 are spaced out from each other. Carpenter's figure in the Challenger Report (pi. 33, 

 fig. 2) is incorrect in the shape of the centrodorsal, which is shown as unnaturally flat- 

 tened. In fact it is almost two-thirds as high as wide at the base. 



All the cirri are lost. 



The radials appear to be short in side view, owing to foreshortening, as they pro- 

 ject from the base of the centrodorsal almost horizontally. They are rounded dorsally. 



The IBri are deeply incised by the apex of the arrowhead-shaped IBr 2 (axillaries) 

 which are widest towards the distal end and have a broadly truncated distal angle with 

 the two distal sides deeply concave. They are slightly longer than wide. 



The articulations between the brachials are hollowed out on the dorsal side to 

 an unusual extent allowing particularly free dorsoventral movement. 



All the pinnules are broken off at the base. 



Locality. Challenger station 160; west of Tasmania (lat. 4242' S.,long. 13410' 

 E.); 4753 meters; temperature 1.05 C.; red clay; March 13, 1874 [P. H. Carpenter, 

 1888] (I.B.M.). 



BATHYMETRA ABYSSICOLA (P. H. Carpenter) 



FIGURE 43 



Antedon abyssicola P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 191 (de- 

 scription, in part; Challenger sta. 244 [the specimen from sta. 160 = B. carpenteri]), pi. 33, fig. 1 



