OPISTHOBRANCHIATE MOLLUSCA. 341 



The body is elevated, evenly rounded ; the mantle well developed posteriorly, 

 slightly longer than the foot, the postero-lateral margins bent inwards towards the 

 foot ; the distance from the branchial opening to the end of the mantle 0'8 centiin. 

 The branchial opening is oval, transversely placed, measuring 5 millims. by 3 millims., 

 its edges raised into a low smooth collar. The edges of the rhinophore pores are 

 slightly raised. The texture of the mantle is firm and spiculose, it is covered with 

 rather small but not very crowded low truncated or flattened tubercles with the ends 

 of the spicules showing through their surface. The front margin of the foot is 

 bilobed, the head is small, the tentacles very small and flattened. 



The radula (Plate II., figs. 18 and 19) consists of about 38 rows. The lateral teeth 

 on each side number 39. The 10 innermost teeth are rather small, hooked, and have 

 a minute denticulation on the outer side. The three outermost teeth are small, the 

 two outermost being fringed and the next simply hooked. 



There are both salivary and ptyaline glands present on the buccal mass. 



The penis and vagina are unarmed, but it is possible, since the genital organs bear 

 a great resemblance to those of Jorunna, that the presence of a stylet may have 

 been overlooked. 



SUB-FAMILY: CHROMODORIDIN^E. 



Chromodoris reticulatus, PEASE. 



One specimen of the above (= Chromodoris alderi, COLLING WOOD) was taken at a 

 depth of 45 fathoms in the Gulf of Manaar, in February, 1902. 



The colour when living, as noted by Professor HERDMAN, was " white speckled 

 with red-brown ; bright yellow border. Gills dark red and white ; long white tail." 



The colour of the preserved specimen is a pale orange-yellow, with fine reddish 

 markings and reticulations, the latter rather wider towards the margin. Branchiae 

 simply pinnate, light red, with two deep red lines running up the inside of the rachis. 

 Rhinophores dark red. Margin of mantle with faint narrow orange line. General 

 colour effect reddish-orange, darkest anteriorly. Length of preserved specimen 

 2'8 centims., width 1'8 centims., height 1'8 centims., width of foot I'l centims. The 

 free margin of mantle is narrow, turned up posteriorly, with median posterior notch. 

 Branchiae 24, arranged in two spirals as in Casella. Pseudo-peritoneum tough, white, 

 but without nodules. 



The radula corresponds very well with the figures given by BERGH for C. reticulatus, 

 and the labial armature is formed of bifid rods, as noted by him. 



I think that there is little doubt but that this species is both the C. reticulatus of 

 PEASE (6, p. 205), and the D. alderi of COLLINGWOOD (8). 



The figure given by COLLINGWOOD is more like it than that which BERGH gives 

 after GARRETT, and shows the notch at the end of the mantle which BERGH does not 

 allude to. The number of branchiae is given by BERGH as 9 to 15, and by COLLINGWOOD 

 as 12, but this seems to be of no specific importance in the genus. 



