228 



DE W. A. HERDMAN ON 



at the posterior end, where there are also root-like prolongations of the test, 

 to which sand is attached. 



The colour is light grey where the test is exposed; reddish-brown from 

 the sand elsewhere. 



Length of the body (average specimen), 1*5 cm.; breadth, "7 cm.; length 

 of the root-like appendages, 1 cm. to 2 cm. 



The test is thin, but moderately tough. It is translucent where free from 

 sand. The posterior end from which the sandy prolongations spring is some- 

 what thickened. 



The mantle is rather slight. The muscle bands are feeble, and not very 

 numerous ; they form an open irregular network. 



The branchial sac has four folds upon each side. Each fold is formed by 

 the aggregation of from six to twelve internal longitudinal bars. There are 

 two to four bars in each interspace. The transverse vessels are of two sizes, 

 alternating regularly. The meshes are much elongated vertically, and contain 

 about three or four stigmata each. The stigmata are long and narrow, and the 

 meshes are divided transversely by a narrow horizontal membrane. 



The dorsal lamina is rather wide, and has irregular and partial transverse 

 ribs ; the margin is smooth. 



The tentacles are numerous, and closely placed. They are large, and all of 

 much the same size. 



The dorsal tubercle is a simple, slightly-curved band, with the extremities 

 directed posteriorly. 



Locality. — Six specimens were dredged in Tangier Bay, on the 5th August 

 1870, from a depth of 35 fathoms. 



There is a characteristic appearance about the specimens of this species, 

 although they all differ somewhat in shape (see Plate XXXVI. figs. 1-3). In 

 all, the apertures are closely placed at the anterior end, the body is elongated 

 antero-posteriorly, and the posterior end is prolonged into a mass of branched 

 projections covered with sand. The dimensions of the six specimens are as 

 follows : — 





A. 



B. 



C. 



D. 



E. 



F. 



Length of body alone, 



2-0 cm. 



1*5 cm. 



l - 5 cm. 



T6 cm. 



1-0 cm. 



1*4 cm. 



Length of posterior projections, 



11 cm. 



0-7 cm. 



2-2 cm. 



1-0 cm. 



l - 4cm. 



2 - 5 cm. 



Breadth of body, 



11 cm. 



0-9 cm. 



07 cm. 



07 cm. 



- 6 cm. 



05 cm. 



The folds in the branchial sac (PI. XXXVI. fig. 5), although they have a con- 



