230 PROCEEBINGS OF THE MILACOLOGICAL SOCIETY. 



The rliinopliore openings are closed, as is also the branchial pocket 

 in the larger specimen. In the smaller it is open and roundish, 

 without teeth or lobes. The branchiae are four, two on each side, 

 the rhachis thick, the branches few and bipinnate, white, but deep 

 red at the tips. 



The formula of the radula is at its maximum about 54 X 40 : : 40. 

 The teeth are simply hamate, crowded, and smaller in the middle. 

 The four or five outermost are somewhat degraded in shape, with 

 fine hair-like denticles on the apex. A trace of the hook sometimes 

 remains in a larger denticle. 



The coloration, dorsal pattern, radula, and branchiae leave no 

 doubt that this is D. tessellata, but I think the genus should be united 

 with Halgerda, Bergh, which appears to have priority as a name, 

 though it is difficult to be sure, as both genera were created in 1880. 

 I cannot find any material difference in his description of the two 

 genera. If they are united the list of species will be as follows : — 



1. ir./or»20Sfl[, Bergh : Verhandl. zool.-botan. Gesell. Wien.,vol.xxx, 



pp. 190-195, pi. iv, figs. 15-20; pi. v, figs. 10-12 (1880). 



2. H. tessellata (Bergh) : Semper's Keisen, Suppl., Heft i, p. 75, 



pi. C, figs. 11-12 ; pi. F, figs. 22-23. 



3. H. maculata, Eliot: Gardiner's Fauna and Geog. Maldive and 



Laccadive Archipel., p. 556 : small, and perhaps an immature 

 specimen of H. IVasinensis. 



4. //. Willei/i, Eliot: Proc. Zool. Soc, 1904, vol. ii, p. 372. 



5. H. Wasinensis, Eliot: I.e., p. 373. 



RizzoLiA MODESTA (?), Bergh. 



BizzoUa modesta, Bergh: Verb. z.-b. Wien., vol. xxx, pp. 156-160, 

 pi. i, figs. 1-11 (1880). 



One specimen from the Inland Sea, Japan, dredged by Mr. Gordon 

 Smith in 85 fathoms. As preserved, it is of a uniform yellow and 

 stoutly built, being 32 mm. long, 9 mm. broad across the pericardium, 

 and 11 mm. high to the top of the pericardium, which is large and 

 prominent. The left side of the head has apparently been bitten off, 

 and only the right oral tentacle remains. It is large and stout, 9 mm. 

 long. The rhinophores are much smaller, being 5-5 mm. long, stout, 

 and set close together, slightly wrinkled, but not perfoliate. 



The cerata are set in eight groups on each side, but the last three or 

 four groups are close together, so that superficially the number seems 

 less. Each group consists of two rows of papillae arranged in a horse- 

 shoe (v. Bcrgh's figures, I.e., pi. i, fig. 1). The first two groups are 

 set on very distinctly projecting prominences ; the remainder are only 

 slightly raised above the level of the back. The first group contains 

 about 14 cerata, none of which are very long. The number of cerata 

 in the living animal is rather greater than is given here, for though 

 they are not very caducous, a good mauj^ have fallen off. There is 

 a considerable interval between this group and the second, which 

 contains 19 cerata, in the midst of which is the anal papilla. The 

 third and fourth groups contain respectively 16 and 14 moderately 



