282 SIR C. liLIOT ox NUDIBKANCHS [Nov. 29, 



is as in the typical Ph. varicosa. This vai-iety when preserved 

 sometimes supei-ficially i-esembles Fh. pustulosa, but I think it 

 should be referred to Ph. varicosa because (1) there are inter- 

 mediate foi'ms ; (2) the bulbus pharjngeus is not black ; (3) the 

 foot is marked with a broad black line. 



Phyllidia (Phyllidiella) xobilts B. (Plate XYI. fig. 1.) 



[Bergh, Bidr. til en Monogr, p. 512 ft". ; & id. S. R. xvi. 2, 

 p. 860 ft'.] 



This species is common, but does not attain a large size, the 

 finest specimen being 36'5 mm. long by 18 broad. The back is 

 black, with sea-green tubercles. The vmder sm-face and branchiae 

 are greenish grey, and there is a yellowish boi'der round the foot. 

 The rhinophores are black. The patterns on the back vary con- 

 siderably, but the ground-plan appears to be in all cases two or 

 three bordei'S running round the mantle and a series of oblong 

 figures in the centre. The tubercles are mostly compound, and 

 sometimes consist of as many as ten small lumps fused together. 

 In one of the most regular specimens there is first a green border 

 showing hardly any traces of tubei-cles (this feature appears 

 invariable), then a circular band of narrow tubercles, then a 

 similar band of much broader and more composite tubercles. 

 Down the centre of the back are arranged four oblong figures ; 

 the sides of each are composed of two tubercles and the top and 

 bottom of one ; within the area are two tubercles. All these 

 prominences are compound, but a number of little simple tubercles 

 are scattered here and there. This arrangement varies consider- 

 ably owing to the borders and figures running into one another. 

 In other cases the central figures are placed accurately one above 

 the other, and the tubercles then appear to be ai'ranged in straight 

 lines. Bergh 's uncoloured plates (S. R., Heft xvi. 2, pi. Ixxxiv. 

 figs. 11 & 18) give a good idea of the animal, but in my specimens 

 the bordeis are more distinct and circular. The drawing in 

 Plate XYI. fig. 1, by Mr. Crossland, is a fair representation of 

 the average East- African specimens, though a little less regular 

 than the one described above. It fails, however, to indicate that 

 all the larger tubercles are compound. In many specimens the 

 green parts have a tendency to coalesce and form blotches, but I 

 have never seen this so highly developed as in the animal figured 

 in Bergh's ' Opisthobranchs of the Danish Expedition to Siam ' 

 (plate ii. fig. 15). 



The opeiiings for the rhinophores and anal papilla are very 

 small and situated in or at the edge of tubercles. The buccal 

 mass is very lai'ge and, like the rest of the intestines, yellow, but 

 in some specimens has a little black pigment in front. 



Phyllidia nobilis, var. rotunda. 



Two specimens constitute a very distinct variety, possibly 

 meriting specific rank. From the absence of notes it may^ 



