20 ART. 1. — CHARLES ELIOT : 



can hardly rank higher than a variety of PL omenta. At present 

 we seem to have three possibly valid species, all of which have 

 practically the same radnla. 



1. PL omenta (Q. & GL), admitted by Bergh. (Siboga p. 136) 

 to be the same as his PL arrogans. Whitish, with dark lines 

 and scarlet blotches. Male genitalia armed with hooks and disks. 



2. PL flammulata Bergh. Brownish with white mottlings and 

 scarlet blotches, the whole plentifully besprinkled with dots or 

 very short lines. Genital ducts with thick, winkled cuticle but 

 no hooks or disks. 



3. PL striata (Kelaart). No red blotches (this is proved by 

 A. & H's drawing) but bold dark lines. Genital ducts as in PL 

 flammulata. 



JRostanga musculo, Abraham. 



See Eliot in Proc. Malac. Soc. Vol. yü, 1907, p. 339, also Mac Farland on E. pulchra U. S. 

 Bull, of Bureau of Fisheries, 1905, Vol. xxv. p. 119, and Cheeseman on Dor-is ruhicunda 

 in Trans. Inst. New Zeal. Vol. xiii, 1880, p. 222. 



One specimen from Misaki 1 6 mm long and 3 mm broad. It 

 is pure white and soft in texture. The back is covered with 

 elongate tubercles from which spicules project. The branchiae are 

 seven and simply pinnate. The edge of the pocket is quite smooth. 



The buccal parts show hardly anything which can be called 

 a labial armature but the labial cuticle bears granules and a few 

 fibrous rods. The teeth are of much the same shape as in R. 

 muscula but the radula is considerably smaller, the formula not 

 exceeding 33x51.0.51. The first lateral next to the rhachis is 

 hamate and bears 20-30 denticles. Then follow about 30 teeth 

 without denticles, hamate but gradually becoming more erect. 

 The last 15 or 20 teeth towards the end of the row are long, erect, 

 thin, and split at the tip into 2-4 long brushlike denticles. 



This specimen seems allied to R. muscula, R. pulchra and R. 

 rubicunda and perhaps should be identified with the first as the 

 absence of a labial armature and the shape of the teeth are 

 common characters. But an examination of more specimens and 

 of the living animal is desirable. 



