HO THE VOYAGE OF H.M.S. CHALLENGER. 



632 fathoms ; bottom temperature, 30°"5 F. Three (or more) specimens. Also at other 

 unrecorded localities in the " cold area." 



H.M.S. Challenger, Station 48, May 8, 1873 ; on the Le Have Bank; lat. 43° 4' N., 

 long. 64° 5' W.; 51 fathoms; rock. Several specimens. 



H.M.S. "Valorous," Station 1, July 22, 1875; off Hare Island, in Davis Strait; 

 lat. 70° 30' N., long. 54° 41' W.; 85 fathoms; sand and mud. One specimen. 



H.M.S. "Alert," 1875 ; Franklin-Pierce Bay in Smith's Sound ; lat. 79° 25' N. 



Other Localities. — Melville Bay ; Jan Mayen ; Spitsbergen Sea : Barents Sea ; Kara 

 Sea ; Coast of Siberia to long. 92° 20' E. (Stuxberg) ; Bay of Fundy 1 (Stimpson). 1 



Remarks. — Although described by Miiller in 1841, this species was never figured till 

 187G, when Quenstedt gave a rough, but very characteristic sketch of it in the Atlas of 

 the Petrefactenkunde Deutschlands, 2 Five years later it was again figured and minutely 

 described by Duncan and Sladen in their well known monograph of Arctic Echinoderms. 

 The numerous examples of it which were dredged by the Challenger off Halifax 

 (Station 48) are by no means so large and well developed as individuals which I have 

 examined from higher latitudes, and notably those obtained in the Barents Sea by the 

 Dutch Arctic Expeditions, which are the finest examples of the type that I have seen. 

 The spread of these Atlantic specimens does not exceed about 40 cm., and there are not 

 more than two hundred arm-joints. The cirri and the lower pinnules are also fewer-jointed 

 and shorter in proportion, while the arm-bases are much less tubercular than in the more 

 northern forms. In these last the junction of the first two brachials forms a somewhat 

 prominent knob in the middle line of the arm, and there is another at the outer end of 

 the hue of articulation between the second and third. The next is at the inner end of 

 the articulation between the third and fourth, the one joint projecting forwards and the 

 other backwards to form a knob-like elevation. This usually disappears at the second 

 syzygy (on the eighth brachial), but may be continued out for three or four joints further, 

 and the result of it is that the fourth to the seventh joints are altogether different from 

 their successors in bearing their pinnules on their shorter sides (PI. XXIV. figs. 10, 11). 

 Beyond the third syzygy the joints are very distinctly triangular, but they are consider- 

 ably wider than long, and this disproportion increases in the middle and outer parts of the 

 arms, so that the successive pinnules are very closely set (PI. XXIV. fig. 13) ; and it is 

 only cpiite at the extremities that the joints become at all quadrate (PI. XXIV. fig. 12). 

 This is one of the best characters for distinguishing Antedon eschrichti from Antedon 

 quadrata (PL XXVI. figs. 1-3 ; PI. XXVII. figs. 5-7 ; fig. 4 on p. 154), which is com- 

 monly found associated with it, though it is shared with Antedon antarctica, as seen in 

 PL XXV. fig. 12. 



1 Stimpson had some hesitation in referring his single specimen to Antedon eschrichti, on account of its small size, 

 and it may not improbably belong to Antedon quadrata. 



2 Encriniden, tab. 96, fig. 26. 



