208 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



and smooth, except at the place of attachment where the 

 test is prolonged into several short tag-like processes. 

 The colour is a light yellowish grey. 



The length is 15 cm. The greatest breadth is 6 mm. 

 and the greatest thickness 5 mm. 



The Test is thin and flexible, but tough, over the greater 

 part of the body. At the posterior end it becomes thicker 

 and cartilaginous. It is white in section. 



The Mantle is very thin, but the muscle bands, though 

 delicate, are numerous. They run both longitudinally and 

 transversely and form a close rectangular network. T he 

 mantle adheres very closely to the inner surface of the 

 test. The sphincters aie strong. 



The Branchial Sac is large, but very delicate and 

 transparent. It has four slight but perfectly distinct folds 

 upon each side. Each fold has about six internal longi- 

 tudinal bars, and there are two bars in each interspace. 

 The bars are narrow, but very regular. The transverse 

 vessels are all of the same size and are moderately wide. 

 They have narrow horizontal membranes, and the meshes 

 are in some places divided horizontally by similar mem- 

 branes which do not interrupt the stigmata. The meshes 

 are nearly square and contain four to six stigmata each 

 (PI. IX., fig. 2). 



The Dorsal Lamina is a very narrow plain membrane 

 with a straight edge and no ribs or other markings. 



The Tentacles are simple. There are about 20, and they 

 are of two sizes placed alternately. 



The A limentary Canal forms a simple and rather narrow 

 loop. The oesophageal aperture is placed far back in 

 the branchial sac. The oesophagus runs posteriorly and 

 ventrally to the narrower end of the ovate stomach which 

 has longitudinal ridges, eight on a side. The intestine at 

 first runs ventrally and then turns anteriorly and then 



