REPORT ON THE CRINOIDEA. 181 



middle and outer portions of the arms (PI. XXXI. figs. 1,4; PI. XXXII. figs. 1, 5, 7). 

 It also differs from Antedon exigua in the greater length of the outer cirrus-joints 

 (PI. XXXII. figs. 3, 8,9). 



Attached to one of the specimens obtained at Station 236 was a single individual 

 of Myzostoma cornutuni, von Graff. 



c Antedon rosacea, Linck, sp. 

 ' \ Antedon petasus, Dtiben and Koren, sp. 



be 

 Specific formula — A.—. 



No Coniatuke which can be referred to either of these closely allied species were 

 dredged by the Challenger, but a single individual which seems to belong to Antedon 

 rosacea was obtained by the " Porcupine " somewhere in the Fasroe Channel ; while five 

 young specimens were met with on the Tunis coast, together with large numbers of 

 Antedon phalangiu/m. Another example of the " Porcupine " variety was obtainedby 

 the "Knight Errant" in 1880, to the north of the Hebrides ; and the "Triton" dredged 

 Antedon petasus on the Fasroe Banks in 1882. 



The mutual relations of these various forms, and of the numerous examples of what 

 is commonly called Antedon rosacea from different localities in Britain *and elsewhere, 

 constitute a problem of no little difficulty, and one which I prefer to leave undecided 

 for the present. I have been collecting the materials for its solution for some years past, 

 and shall hope in course of time to be able to arrive at a definite opinion on the subject. 



Antedon rosacea has been described by G-reeff as occurring at the Canary Islands and 

 even at the Equatorial Island of Rolas, 1 in the Gulf of Guinea. But the question 

 whether the forms mentioned by him are identical with the North British variety which 

 goes by the same name, is one which cannot be definitely decided without a careful 

 comparison of the individuals in question and of others from intermediate localities. 



7. Antedon diibeni, Bohlsche (PI. XXXVII. figs. 1-3). 



Specific formula — A.—. 



1866. Antedon Dubenii, Bohlsche, Archiv f. Naturgeseh., 1866, Ed. i. p. 9. 



1868. Antedon Dubenii (?), Verrill, Trans. Connect. Acad., 1868, vol. i. p. 365. 



1879. Antedon Dubenii, P. H. Carpenter, Trans. Linn. Soc. Lond. (Zool.), ser. 2, 1879, vol. ii. p. 29. 



1882. Antedon dubeni, Bell, Proc. Zool. Soc. Lond., 1882, p. 534. 



1883. Antedon dubeni, P. H. Carpenter, Proc. Zool. Soc. Lond., 1882 [1883], p. 746. 



Centro-dorsal a slightly convex pentagonal disk, bearing from thirty to forty cirri, 

 which have from twelve to fifteen smooth joints, the outer ones stouter than those at the 

 base, laterally compressed, and rather longer than wide. 



1 Echinodermen, beobachtet auf einer Reise nach der Guinea-Insel Sao Thome, Zool. Anzeiger, 1882, Jahrg. 5, 

 pp. 116, 159. 



