6 W. G. RIDEWOOD. 
stolon (10, p. 52), and Harmer also states that deserted stolons of this species are 
deeply pigmented (10, p. 93). The red line of the buccal shield is absolutely constant, 
being present even in the shield of the reduced males of C. stbogae. The red pigment 
of the oviduct is also constant, and is sometimes, though rarely, present in the testis- 
duct in C. nigrescens and C. hodgsoni. Harmer, by saying nothing of red pigment 
around the testicular orifices in C. stbogae, leads one to conclude that there is none. 
The free ova found in the cavities of the tubarium in some of the species vary some- 
what in size, although they are all heavily yolked, and are all ovoid in shape, and pale 
yellow in colour. Those of C. nigrescens are the largest, and measure ‘6 mm. across ; 
those of C. hodgsoni are 4°5 mm.; and those of C. dodecalophus, C. gracilis, and 
C. levinsent measure between *3 and *4 mm. 
Trxt-FicurE 3.—Cephalodiscus levinseni, portion of a branch (x 5). The dark bodies are the polypides. Hach 
polypide occupies a separate cavity of the tubarium, opening by a single ostium. (Copied from Harmer, 10, 
plate 2, fig. 11.) 
One is thus left with the tubarium to deal with, and the architectural details 
of the test are almost in themselves sufficient to enable one to judge of the species 
to which the polypides that produced it belong. The size and ‘habit’ of the 
tubarium of the different species are much more different than are the size and 
shape of the polypides. The colony of C. gracilis and C. sibogae (text-fig. 2) is 
diminutive, that of C. nigrescens is exceptionally bulky and massive. The branching 
of C. dodecalophus is straggling, the branches of C. hodgsoni are more closely set. 
The spine-like processes of the exterior of the tubarium vary in length and thickness 
in the different species; they may occur one to each ostium, or several, or may 
occur apparently independently of the ostia. They may be long, thin spines, or 
