128 SIDNEY F. HARMER. 
6. Bugula avicularia, L.} 
This form grows in short, bushy tufts, of a grey colour. 
The avicularia are usually large, although they vary a good 
deal in size; they are, in many cases, absent on the older 
parts of the colony, and are hence probably deciduous. The 
three spines on the upper margin of the aperture are very 
small in most of the specimens which I obtained at Naples. 
The Neapolitan form of this species has been well figured by 
Claparéde.” 
The funicular tissue contains no pigment. ‘ Leucocytes” 
similar to those of B. neritina occur in the meshes of the 
connective tissue, and are either colourless or distinctly 
brownish grey. The colour, if any, is contained in a diffuse 
form in the vacuoles which compose most of the cell, and 
which sometimes contain, in addition, one or two minute 
granules. The connective tissue of this species will be 
described more fully in the later parts of this paper. 
The pharynx and intestine are colourless. Yellowish-brown 
granules occur in the walls of the proventriculus, cecum, 
and part of the stomach, the granules being most numerous 
in the cecum. A _ saddle-shaped area at the base of the 
cecum is devoid of granules (Pl. III, fig. 16°), just as was 
the case in B. neritina. 
The walls of the rectum contain granules, which are either 
almost colourless or are faintly yellow in tinge. 
ce. Flustra papyrea, Pall. 
The ordinary funicular tissue may be non-granular, or may 
1 This is probably referred to by Costa (loc. cit.) as one of the forms 
assumed by B. neritina. This “second generation ”’ arises from the “ piedi 
della prima,” and is “ bianchissima, translucida come il cristallo, fragillissima.” 
The individuals figured by Costa on Tav. vi possessed avicularia, and pre- 
sumably belonged to this species. 
2 ¢Zeits. f. wiss. Zool.,’ Bd. xxi, Taf. viii, figs. 1, 1 B. 
’ The granules are, indeed, not represented in this figure; but the blue or 
green colour, due to the indigo-carmine which had been taken up by this 
individual, gives a perfectly correct idea of their distribution. 
