AMPHIURIDAR 297 



Both specimens have the mouth very widely open. The disk is partly loosened from 

 the arms and has contracted a little so as to become somewhat concave. The species 

 appears to be liable to lose its disk. 



This species appears to be the nearest related to the Japanese species Amphiodia 

 digittila of H. L. Clark (North Pacific Ophiurans, p. 162, fig. 70; Matsumoto, Mono- 

 graph of Japanese Ophiuroidea, p. 199, fig. 54) in which there is likewise a small spiny 

 plate outside the radial shields. That the latter is referred to the genus Amphiodia, the 

 present species to Amp/iiop/m, is no serious objection to regarding them as related, the 

 distinction between these genera not being sharp. As pointed out by Matsumoto the 

 mouth papillae of A. digitida approach those of Amphiopliis, and the present species 

 might perhaps rather be referred to Amphiodia— it all depends on how strictly we limit 

 those genera according to the number of the mouth papillae. 



The character of the mouth papillae of the present species also recalls Amphioplus 

 acntiis (cf. Fig. 26 a, p. 295), but evidently there is no near relation between these two 

 species. 



Possibly the specimens in hand are only young ones ; as they have been dried the 

 condition of the genital organs cannot be ascertained. 



Amphioplus peregrinator, Koehler 



(Plate VII, figs. 12-15) 



Amphioplus peregrinator, Koehler, 1912. IP Exped. Antarct. Fran9aise. Echinodermes, p. 135, 

 pi. xi, figs. 5, 11-12. 



5. 2. iii. 27. Bransfield Strait, South Shetlands, 200 m. i specimen. 



). II. iii. 27. Schollaert Channel, Palmer Archipelago, 160 m. 6 specimens. 



[. 12. iii. 27. Schollaert Channel, Palmer Archipelago, 160-335 m. i specimen. 



>. 14. iii. 27. Schollaert Channel, Palmer Archipelago, 278-500 m. i specimen. 



J. 16. iii. 27. Fournier Bay, Anvers Island, Palmer Archipelago, 295 m. i specimen. 



7. 18. iii. 27. Neumayr Channel, Palmer Archipelago, 259-354 m. 2 specimens. 



D. 24. iii. 27. Bismarck Strait, Palmer Archipelago, 98-130 m. 6 specimens. 



There can be no doubt about the identity of these specimens with Koehler's Amphio- 

 plus peregrinator , described {op. cit.) from a single specimen collected by the ' Pourquoi- 

 Pas? '. Some additional information may be gathered from these specimens, the largest 

 of which reach a diameter of disk of c« . 1 1 mm . The incision in the interradial edges of the 

 disk is not a constant character of the species ; on the contrary, the disk, particularly in 

 the larger specimens, often bulges out interradially, and may be considerably swollen. 

 The proximal ventral plates are usually somewhat elevated. The arm spines are often 

 four on the proximal joints in the larger specimens. The primary disk plates are usually 

 very conspicuous, particularly in the young specimens. 



The specimen from St. 182 shows distinct traces of colour; the ventral side of the 

 arms and the adoral shields are a conspicuous orange, the same colour being also found 

 on the radial shields and the primary plates of the disk. Also in dried specimens these 

 plates may stand out lighter against the general dark grey colour of the disk. In the 



13-2 



