229 



ON SOME NUDIBRANCHS FROM THE PACIFIC, INCLUDING 

 A NEW GENUS, CHROMOBORIBELLA. 



By Sir C. K E. Eliot, K.C.M.G. 



Read IZth January, 1905. 



The Nudibranchs described in this paper have been derived from 

 various sources, and consist of (1) Dictyodoris tessellata from Madagascar, 

 (2)^/z3o/m /»or/<?s^« and C7i'romo(:?om^e^ec7im/es from Japan, (S) Abraham's 

 Doris Wellingtonensis from New Zealand, which has been referred to 

 Doridopsis, but is here shown to be an Archidoris or Anisodoris, 

 (4) a small collection sent by Mr. Burnup from Scotsburg, Natal, 

 about 30° S., consisting of Chromodoris runcinata, lineafa, and annulata, 

 Chromodoridella mirabilis, gen. et sp. nov., and Hexahranclmsi^) 

 Adamsii. Considering the latitude of the locality, this last-named 

 collection is remarkably equatorial in character. Of the other species, 

 Dictyodoris tessellata has hitherto been recorded from the Palm Islands 

 and Ch. petechialis from Hawaii, so that, as usual, the forms appear 

 to be widely distributed over the Indo-African-Pacific area. 



DiCTTODOKIS TESSELLATA, Bergh. 



Dictyodoris tessellata, Bergh : Semper's Reisen Archipel. Philippin , 

 Theil iv, Heft 1, pp. 75-78, pi. C, figs. 11-12; pi. E, figs. 22-23. 



Two specimens from Madagascar were kindly given me by Professor 

 Yoltzkow. The label bears the inscription " Bai v. Tulear, S.W. 

 Madagask. Riff am Steinen." They are clearly of the same species, 

 but one is nearly twice as large as the other. The measurements 

 of the larger are: length 22-5 mm., breadth 18, height 9. The 

 mantle-edge is ample, being 7 mm. wide at the sides and 5 over the 

 head and tail. 



The texture is like a hard clear jelly. On the back is an elaborate 

 reticulate or stellate pattern, which is much more developed in the 

 larger than in the smaller specimen. Its genesis seems to be that 

 there are three doi'sal ridges bearing three or four tubercles each. 

 These tubercles are then connected by secondary ridges. Tertiary 

 ridges extend towards the middle of the figures thus formed, and 

 towards the mantle-edge, but are little developed in the smaller 

 specimen. The ridges are white in the smaller, pale purple in the 

 larger specimen. In both the colour between the ridges is brownish 

 purple, with numerous round white dots. Round the mantle runs 

 a purplish-white border. The foot is bluish white. There are 

 purple spots on the under side of the mantle, and a purple band at 

 the junction of the foot and body. The foot shows no sign of an 

 anterior groove or notch, but is much contracted. 



