32 THE AUSTRALIAN MUSEUM. 



This small Cynthia has a very remarkable test. The surface is hard 

 and gritty to the feel when cut. Thin sections of the surface show that 

 there are large numbers of calcareous spicules of stellate and spherical 

 form imbedded in the superficial layer (PI. Cyn. XI, fig. 3). The 

 spicules appear to commence as minute granules, which become stellate 

 (fig. 4). Then the number of rays increases greatly, and the tips broaden 

 and flatten out, and the spicule becomes a sphere or ellipsoid covered 

 with small flat bosses (fig. 3). 



The larger specimen of this Cynthia (fig. 1) is joined on to two 

 specimens of Styela personata, n. sp. It shows the tag-like processes of 

 the test, especially around the apertures. There are also two very 

 much smaller specimens, one 8 mm. across (fig. 2), and the other 5 mm., 

 which have long branched root-like processes of test at the posterior end. 



There are no atrial tentacles, but there is a slight diaphragm at the 

 base of the atrial siphon which ends in short rounded lobes or projections 

 (fig. 7). The lining of the atrial siphon contains a network of blood 

 vessels, in some of which are fusiform or triradiate spicules, rather like 

 those found in the genus Culeolus. 



Strong radial muscles radiate from the bases of the siphons and inter- 

 lace with circular muscles to form a strong network. 



The 6 larger tentacles (see fig. 6) are very much branched. The 

 meshes in the branchial sac are of very different sizes, as the internal 

 longitudinal bars between the folds (fig. 5) are by no means equidistant. 



The gonads form a number of angular yellow masses placed both in 

 the intestinal loop, and also over the right side of the mantle. These 

 masses are united on each side of the body by delicate ducts. 



Cynthia spinifera, n. sp., PL Cyn. X., figs. 1 12. 



External appearance. Shape nearly globular, attached by a small 

 flattened area at the posterior end. No lateral compression. Apertures 

 both on the rounded anterior end, moderately far apart, sessile, and 

 not conspicuous. Surface covered with remarkably long, branched, and 

 echinated spines, which are especially well -developed in two tufts on the 

 anterior end close to the apertures. Colour dull greyish brown. Size 

 1-5 cm. by 1-3 cm. by 1-3 cm. 



Test rather thin but tough, covered on its surface with large and 

 small spines. 



Mantle of a yellow brown colour, muscular ; siphons short. 



Branchial sac with 6 folds on each side. Internal longitudinal bars 

 8 on a fold and 4 in the interspace. Transverse vessels alternately larger 



