V 



REPORT ON THE TUNICATA. 163 



fig. 10). The apertures arc sessile and inconspicuous, and in their present contracted 

 condition appear to be scarcely lobed. The test is coriaceous and tough, coloured dark 

 reddish-brown upon the outside, and white internally. 



The folds in the branchial sac are in the same rudimentary condition as in the two 

 preceding species. On the folds there are about five closely placed internal longitudinal 

 bars, and between these regions there are about the same number of bars placed further 

 apart. The meshes in the spaces between the folds are elongated antero-posteriorly, 

 and contain each three stigmata. The transverse vessels are of two very distinct sizes 

 (PI. XX. fig. 11, tr. and tr.') placed alternately, while a still smaller size (//•."), in the 

 form of a delicate bar, stretches across each row of meshes. Very delicate muscle-fibres 

 are visible in the transverse vessels, and also in the fine longitudinal interstigmatic 

 vessels (PI. XX. fig. 12, which shows also the mode of union of the delicate hori- 

 zontal bar (tr.") with the internal longitudinal bar, i.l.). Figure 13 on Plate XX. 

 represents the posterior end of the ventral edge of the sac, to show the lower extremity 

 of the endostyle (en.), and the ridge which is continued from it round the end of the 

 branchial sac to join the posterior extremity of the dorsal lamina. This figure also 

 shows how the internal longitudinal bars (i.l.) join the flat membrane at the lower end 

 of the branchial sac. 



One specimen of Styela glans was dredged in the South Atlantic, off the coast of 

 Buenos Ayres, at Station 320; February 14, 1S7G ; lat. 37° 17' S., long. 53° 52' \Y.; 

 depth, 600 fathoms ; bottom temperature, 2° - 7 C. ; bottom, hard ground. 



Styela radicosa, n. sp. (PI. XXIV. figs. 6 and 7). 



External Appearance. — The body is elongated, ovate or pyriform in shape ; it is not 

 compressed, and is attached by the posterior end. The anterior end is produced and 

 pointed, the posterior is broad and rounded, and is prolonged at the edges into several 

 long branched processes for attachment. The dorsal and ventral edges are nearly straight, 

 and converge towards the narrow anterior end ; the dorsal is more convex than the ventral. 

 The branchial aperture is terminal ; it is sessile but conspicuous, is indistinctly lobed, 

 and is directed anteriorly and ventrally ; the atrial is on the dorsal edge, one-third of 

 the way down ; it is sessile but conspicuous, and indistinctly lobed, and it is directed 

 dorsally. 



The surface is even and nearly smooth, in some places it is finely wrinkled trans- 

 versely, and more rarely longitudinally; it is slightly corrugated around the branchial 

 and atrial apertures. The colour is made up of various shades of creamy white, buff, and 

 yellowish-brown, being lighter towards the posterior end and darker on the anterior end, 

 and especially around the branchial aperture. 



Length (antero-posterior, not including the root-like processes), 4*5 cm.; breadth 

 (dorso-ventral), 2*8 cm. ; thickness (lateral, at posterior end), 2'2 cm. 



(ZOOL. CHALL. EXF.— PART XVII. 1882.) J; 22 



