230 DISCOVERY REPORTS 



None of the present specimens exceed a length of 33 mm. As none of the other 

 specimens known exceed a length of 38 mm. (the type specimen) it is evident that this is 

 about the maximum size of this species, which is, accordingly, noticeably smaller than 

 the other species of the genus Amphipneustes. 



In my description of this species {op. cit., 1910) I was unable to decide whether young 

 specimens have a fasciole. The large material now at hand, containing specimens of all 

 stages, allows this question to be settled. As was to be expected there is not the slightest 

 trace of a fasciole at any stage of development and growth. 



In the type specimen {op. cit., p. 96, pi. xi, fig. 18) the labrum was found to reach as far 

 backwards as the middle of the second ambulacral plate. This is a rather unusual con- 

 dition. Generally it reaches only to the middle of the first ambulacral plate ; but it is 

 sometimes more elongate, so as to reach to the middle of the second ambulacral plate. 

 This has nothing to do with age ; the elongate condition of the labrum may be found in 

 quite young specimens and, on the other hand, the short labrum in adult specimens. 

 Sometimes the labrum ends opposite the middle of the first ambulacral plate on one 

 side, of the second on the other side; in such a case the first ambulacral plate on the 

 one side is conspicuously produced posteriorly. 



The genital pores appear at a size of about 12-15 mm. length. 



It would appear that the embryos leave the marsupium at a somewhat earlier stage 

 than in A. Lorioli or similis. 



Amphipneustes Lorioli, Koehler 

 (Plate III, figs. 5-8; Plate IV, fig. 8; Plate IX, fig. 27) 

 Amphipneustes Lorioli, Koehler, 1901. Result. Voyage ' Belgica '. Echinides et Ophiures, p. 12, 



pis. ii, fig. 12; V, fig. 37; vi, figs. 42, 43. 

 A. Lorioli, Mortensen, 1910. Swedish South Polar Exped. Echinoidea, p. 91, pis. xi, figs. 17, 



19; xix, figs. 1-2, 6, 10-12, 17, 22, 26. 

 A. Mortenseni, Koehler, 1912. IP Exped. Antarct. Fran9aise. Echinodermes, p. 176, pi. xv, 



figs. ii-i7;xvi, figs. 1-5. 

 A. Lorioli, H. L. Clark, 1917. Hawaiian Echini. Echinoneidae . . . Spatangidae, p. 163. 

 A. Lorioli, H. L. Clark, 1925. Cat. Recent Sea-Urchins Brit. Mus., p. 198. 



St. 181. 12. iii. 27. Schollaert Channel, Palmer Archipelago, 160-335 m. 4 specimens. 

 St. 182. 14. iii. 27. Schollaert Channel, Palmer Archipelago, 278-500 m. 4 specimens. 

 St. 600. 17.1.31. 67° 09' S, 69° 27' W, oft" Adelaide Island, 487-512 m. i specimen. 



Three of the specimens are females. As shown in Plate III, figs. 5, 6 and Plate IV, 

 fig. 8, there is a conspicuous variation in the development of the petals ; also the general 

 shape of the large specimen (Plate III, fig. 6) is somewhat different from that of the 

 other specimens, it being distinctly higher than the other specimens, and somewhat 

 more flattened on top. 



It is a curious fact that the marsupia of two of the specimens are quite empty ; the 

 third contains only very few embryos and eggs, three stages of development bemg 

 represented. The largest embryos, which are 3 mm. long and just ready to leave the 

 marsupium, do not show any trace of a fasciole. Pedicellariae have not yet been 



