86 THE VOYAGE OF H.M.S. CHALLENGER. 



At its anterior end the endostyle is continued forwards in front of the peripha- 

 ryngeal bands (PI. IX. fig. 4, cii.). 



At one point on the ventral edge of the body, near the middle of the endostyle, 

 there is a small cubical outgrowth from the mantle into the test (see PL IX. figs. 1 

 and 8). 



The dorsal lamina is in a most remarkable condition in the single specimen (PL IX. 

 fig. 4, &c., d.l.). Its anterior part forms a short, curved, clubdike projection from the 

 dorsal edge of the branchial sac close behind the peripharyngeal bands. It is strongly 

 marked with transverse ridges and grooves. There is also a similar smaller projection 

 from the dorsal edge of the oesophageal aperture (PL IX. fig. 6), which is probably the 

 posterior end of the dorsal lamina. 



The nerve ganglion is small and rounded. It lies immediately in front of the 

 anterior muscle bands (PL IX. fig. 4, n.g.). It has two laterally-placed curved 

 appendages which lie on its sides and anterior end. The dorsal tubercle is immedi- 

 ately in front of the ganglion, and in its appearance recalls that of some of the Simple 

 Ascidians. 



Cyclosalpa, Blainville. 



. Thalia, Browne, Hist, of Jamaica, London, 175G. 

 Holothuria, Linn., Sy.st. Nat., ed. x. 1758 (in part). 

 Salpa, Forskahl, Descr. anim., 1775 (in part). 



Cyclosalpa, Blainville, Diet, des Sci. Nat., torn, xlvii. p. 94, " Salpa," 1827. 

 Orthoccela, Macdonald, Trans. Roy. Soc. Edin., vol. xxiii. p. 181, 18G4. 

 Pyrosomopsis (?), Macdonald, t.c, p. 180. 

 Salpa, Cuvier, Lamarck, Chamisso, Vogt, Costa, Leuckart, Todaro, Traustedt, &c. (in part). 



Body not attached, elongated, with the apertures at the opposite ends. 



Test gelatinous and transparent. 



Mantle with muscle bands, which form incomplete rings. 



Branchial Sac forming with the peribranchial cavity a large central space. 



Dorsal Lamina a vascular Ijand which traverses the combined branchial and 



peribranchial cavities from the dorsal and anterior to the ventral and 



posterior ends. 

 Alimentary Canal stretched out along the ventral surface of the body ; no 



" nucleus " or visceral mass. 

 Emhryonic Chain in the form of a circle or ring of from seven to twelve 



Ascidiozooids attached together. 



I consider it best to raise the little group of species aUied to Cyclosalpa pinnata 

 once more to the dignity of a genus under the name introduced by Blainville in 



