CATALOGUE OP TUNICATA. 57 



Mantle moderately muscular. The long siphons are surrounded by 

 circular fibres, and radiating bundles issue from their bases. 



Branchial sac with 7 folds on each side, with about 6 bars on a fold. 

 The stigmata are straight and regularly arranged at the base of a fold, 

 but more or less curved elsewhere, and in some places arranged in spiral 

 infundibula. 



The dorsal lamina is a plain membrane. 



The tentacles are 12 large and 12 smaller, placed alternately. 



The dorsal tubercle is a simple crescent-shaped slit, with the aperture 

 placed laterally. 



Locality. Port Jackson ; one specimen. 



This single specimen differs from most species of Molgula in being 

 attached by the greater part of one side, and in having the long recurved 

 siphons (PL Cyn. VI., fig. 9). When the body is taken out of the test 

 (figs. 10 and 11) the siphons are seen to be marked by 6 and 4 echinated 

 ridges. The siphons are opaque brown, the rest of the mantle trans- 

 parent. The branchial sac (fig. 12) has no special character, and the 

 dorsal tubercle (fig. 13) is remarkable for its simple condition. The 

 gonad on each side shows an ovary in the centre and a mass of spermatic 

 vesicles around it. 



Ascopera, Herdm., 1880. 



The following species seems nearer to this genus than to Molgula, 

 but may come to be regarded as an antiectant form. 



Ascopera nana, n. sp., PI. Mol. I., figs. 1014. 



External appearance. Body urn-shaped, with a swollen body, and 

 sometimes a short median posterior stalk. Apertures both at the wide 

 anterior end, but placed at its extremities so as to be rather far apart. 

 Both apertures on prominent papillae turned in opposite directions, the 

 branchial ventrally and the atrial dorsally. Surface a little wrinkled, 

 but otherwise smooth, with only a very few shell and sand fragments 

 adhering towards the posterior end. Length 2-5 cm., breadth 2 cm. 



Test leathery and tough, with only a few short hair-like projections. 



Mantle stronger and more opaque than is usual. Siphons very thick, 

 almost globular. 



Branchial sac with 7 folds on each side. Longitudinal vessels regular 

 and of moderate size. Transverse vessels in places very wide, and quite 

 irregular. Stigmata in some places very small and rounded, quite 



