REPORT ON THE CRINOIDEA. 137 



Apart from the absence of any lateral flattening of the rays and arm-bases and of an 

 ambulacral skeleton, the special character distinguishing the Eschrichti-gcoxnp is the 

 flagellate appearance of the proximal pinnules. The two first pairs (on second to fifth 

 brachials), and sometimes also the third pinnule on the outer side of the arm (on sixth 

 brachial), consist of a large number of short and wide joints, the later ones of which are 

 often somewhat serrate (PL XXIV. figs. 1, 2, 7, 8 ; PL XXV. figs. 1, 2 ; PL XXVII. 

 figs. 8, 9, II, 12, 14, 15). The cirri are always numerous and composed of thirty to 

 fifty joints ; while the long arms bear numerous closely set pinnules, so as to give a very 

 feathery appearance to the general plume; The regular arrangement of the syzygies too 

 is very striking as compared with the Basicurva-grou]), the members of which exhibit 

 hardly any regularity in the grouping of the syzygies, except for the presence of one in 

 the third brachial as in most Comatula3 with articulated radials. In the JEschrichti-groujp, 

 however, as also in Antedon jyhalangium, Antedon rosacea, and allied species, the 

 syzygies are situated with great uniformity in the third, eighth, and twelfth brachials, 

 and afterwards at intervals of two or three joints. The position of the third syzygy is 

 less constant than that of the second, but does not vary to any great extent (PL XXIV. 

 fig. 11 ; PL XXV. fig. 12 ; Pis. XXVL, XXVIII.). 



It will be seen from the following table that the differences between the individual 

 species mostly turn upon the characters of the third pinnule, the relative shape of the 

 arm-joints, and the number of the cirrus-joints. Antedon rhomboidea and Antedon 

 barentsi are species based upon single individuals ; but I have seen seven examples of 

 Antedon australis, and a considerable number of each of the other four species, those of 

 Antedon esehrichti and of Antedon quadrata being from several different localities. 

 Neither Antedon barentsi nor Antedon magellanica were obtained by the Challenger 

 at all, the former living in the Barents Sea, 1 wlule Antedon magellanica was obtained by 

 H.M.S. " Alert," and was described as a variety of Antedon esehrichti by Bell. 2 I have 

 pointed out elsewhere, 3 however, that it is altogether separated from Antedon esehrichti 

 by the characters of its arm-joints, a point to which Bell did not refer, and I have since 

 examined several individuals of it which were dredged by the Italian corvette " Vettor 

 Pisani," and have no doubt whatever as to its being a good species. Although not 

 Challenger species, these two are included in the following list for the sake of 

 completeness. 



!The Comatulje of the "Willem Barents" Expeditions, 1880 and 1881, Bijdragm tot de THerkunde, 1886, 13 

 Aflevering, vi. pp. 1-12. 



2 Note on a Crinoid from the Straits of Magellan, Proc. Zool. Soc. Lond., 1882, p. 651. 



3 Bijdragen tot de Dierkunde, 1886, 13 Aflevering, vi. p. 4. 



(ZOOL. CHALL. EXP. — PART LX. — 1887.) OoO 18 



