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



Antedon milberti or Aritedon comata, P. H. C. On neither of these Crinoids have 

 Myzostomida been hitherto described. The third specimen was obtained from Antedon 

 incisa, P. H. C. (Station 170, ChalL Exp.), and presents some resemblance in form, 

 thickness, and translucent marginal zone to Myzostoma hrevipes (Report, No. 16). Its 

 diameter measures 2*2 mm.; the ten marginal cirri are about 0-14 mm. in length ; the 

 colour of the body is dirty yellow. The back bears five pairs of low but sharply angled 

 radial ridges. All the other specimens admitted of identification. 



2. Myzostoma longipes, Graff. 



Myzostoma longipes, GraflF, Bull. Mus. Comp. Zocil. Cambridge, vol. xi. p. 126, 1883. 



6. Myzostoma alatum, Graff. 



Myzostoma alatum, Graff, Proc, Eoy. Soc. Edin., vol. xii. p. 379, 1884. 



This Myzostoma, found on Antedon phalangium, Miill. sp., off Carthagena in 80 

 fathoms of water (by H.M.S. "Porcupine," 1870), is a species new to the Mediterranean 

 fiiuna. In size (3-5 mm. in longitudinal diameter), colour, and form, it exactly resembles 

 the specimen figured in the Report (pi. i.), except that on the back the insertions of 

 the parapodia appear as sharply projecting bosses, on the apex of which the base of the 

 hook could be seen as a small tubercle. The thin marginal portion reveals without any 

 treatment, but better still after saturating with glycerine, the very abundant, wide, 

 and thickly crowded intestinal branches, which like the ova extend close to the margin of 

 the disc. 



The animal was situated between the mouth and anal-tube of its host, in part astride 

 of the anal tube, and with its pharynx turned towards the oral margin of the Antedon. 

 It was very firmly attached.^ 



10. Myzostoma glahrum, F. S. Leuckart. 



Myzostoma glabrum, Beard, Mittheil. Zool. Stat. Neapel, Leipzig, vol. v., 1885. 



„ „ Nansen, Bidrag til Myzostomernes Anatorai og Histologi, Bergen, 1885. 



„ „ "Wagner, Das Nervensystem von Myzostoma, Graz, 1886. 



A new host for this species is Antedon petasus (Diib. and Kor.), from which Carpenter 

 sent me two specimens (0'6 and 1"5 mm. in diameter). 



11. Myzostoma gigas, Llitken (PL II. fig. 4). 



Myzostoma gigas, Graff, Proc. Eoy. Soc. Edin., vol. xii. p. 378, 1884. 

 „ ,, Nansen, Op. cit. 



Of two specimens from Antedon eschrichti, MiiU. sp., from Station 48 of the Challenger 

 Expedition, the one measured 175 mm., the other 2 mm. in longitudinal diameter, and 



1 Station 13 of the "Porcupine" Expedition of 1870, where this species was also obtained, is in the Atlantic, ofi' 

 Mondego on the Portuguese Coast, and not off Duncansby Head as given on p. 32 of the Eeport. 



