31t HECORDS OF TlIK ACSTRAMAN Ml'SErM. 



Onchidicm amhigudm, Semper. 



Oiichidiniu amhlguum, Semper, Reis. im Arch. Phil., iii., Landmoll, v., 



1880, p. 264, taf. xx., fig. 5., taf. xxi., figs. 22, 24. 

 ? OnchidiuDi vaiylense (Qnoy and Gaimard), Semper, Reis. im Arcli. P)iil., 



iii., Laiidmoll., vi., 1880, p. 289. 



External characters. — Body gh)bnlar, back not strongly' arched. 

 Mantle border smooth, underside flat. Tentacles sliort, eyes at the tip 

 ringed with olive. Head very large and projecting beyond the mantle 

 border. Hypouota smaller than the greatest width of the foot sole. 



Average size: Lengtli 18-19 mm., breadth 11-12 mm., height 8 mm. ; 

 greatest width of the foot sole 5-6 mm. 



Mantle xcalptvre. — The mantle is I'egularly covered with small gran- 

 ules which are somewhat massed in the middle field. The eyes appear as 

 dark points on the eye papilla^, even Avith the naked eye. Tlie eyes may 

 be single, and not more than four ai-e present in a group. 



Colour. — The ground colour of the mantle is yellowish witli a variable 

 and slightly dai'ker pattern. Underside a dirty yellow. 



Position of opeiiinii!<. — The anus is situated on a very small papilla, 

 paith' protected by the foot ; the respiratory opening in the median line 

 is closer to the anus than to tlie mantle border. Male and female openings 

 typical of the genus. 



Anatomy. — Described and figured in part by Semper. 



Group character. — Cartilaginous hooks and tube present in the penis. 



Locality. — Pelew Island, North Pacific (type locality, Semper) : Dunk 

 Island, Queensland (Australian Museum). 



ONCHiDir:\i VAIOIENSE, Qnoy ami (tainiarJ. 



Oiichidlnm vaicflense, Quoy and Gaimard, Voy. de r"rrniiie" ct "Phvsic- 



ienne", Zool., 1824," p. 429. Id., Plate, Zool. .laliih., .\nat.,"vii., 



189:3, p. 175, taf. vii., fig. 10, taf. xi., fig. 79. 

 Onchidium vaigleiisifi (Quoy and Gaimard), Tappaionc CanelVi., Kami. 



Mai. N.Guinea, 1883, p. 213. 

 ? Onchidinvi anibigmtm, Sempej', Reis. im Arch. Phil., iii., Laiidmoil., vi., 



1882, p. 289. 



External character.-^. — Body broadly oval, almost rounded, back 

 strongly arched. Head small, tentacles slioi-t and cylindrical. Hypouota 

 flat, and smaller or equal to the gi-eatest width of tlic loot sole. 



Average size: Lengtli 22 mm., breadth li) mm., height l;)-5 nun.: 

 greatest widtli of the foot sole 10 mm. 



Mantle scnlptnre. — A regularly fine gi'anulation covers the whole of 

 the mantle ; the grannies are of tlie same size, and each possesses a minute 

 light spot marking a glandular opening. In the middle field three or four 

 are recognisable, placed closely t<igethei'. 



pDlonr.-The colouring is very bright and this species in life is the 

 most brilliantly colouj-ed one of the family, 'i'he grcmnd colour is light 

 yellow., and the wliole of the mantle surface is marbled with darker vellow 



