UK PORT ON Till: Tl NK 'ATA. 235 



tenella, which is also closely allied to Ciona in/rsfiualis. Finally, the Challenger expe- 

 dition has discovered two new species, which 1 have dedicated to the founders of the 

 genus, Savigny and Fleming. 



Ciona flemingi, Herdman (PI. XXXIV. figs. 7-10). 



Ciona flemingi, Herdman, Prelim. Rep., Proc. Eoy. Soc. Edin., 1879-80, p. 4G1. 



External Appearance. — The body is somewhat pyriform and elongated; the anterior 

 end is wide, and the posterior much narrower, forming a short stalk turned vent rally, and 

 attached to some foreign body by the extremity of its right side. The apertures are 

 situated at the anterior end, and are inconspicuous; the branchial is near the ventral 

 edge, the atrial is near the dorsal edge; they are equally far forward, the most anterior 

 point of the body being placed between them. 



The surface is smooth ; the colour is light grey. 



Length of the body, 2 '2 cm. ; breadth of the body, 8 mm. 



Tlie Test is thin, soft, and almost gelatinous ; it is transparent, the body showing 

 through distinctly. The vessels are few. 



The Mantle is normal ; the musculature is rather feebly developed, consisting chiefly 

 of a few straight bundles running longitudinally. 



The Branchial Sac is rather thick, small, and shrunken-looking. The transverse 

 vessels are all of much the same size. The internal longitudinal bars are coarse and strong ; 

 they are much crumpled, and bear irregular knob-like papillge at their intersections 

 with the transverse vessels ; no intermediate papillae are present. The meshes have their 

 greatest extent longitudinal, and contain each two to three elongate-elliptical stigmata. 



The Dorsal Lamina is reduced to a series of languets. Each is short ami stout, and 

 has a hook or tusk-like form. 



TJtc Tentacles are simple, all of one length, and twelve in number. 



TJie Dorsal Tubercle is cordate, small, and has both horns turned inwards. 



TJie Viscera extend beyond the branchial sac posteriorly. 



This little species seems to be distinct from the i'rw species hitherto referred to the 

 genus. The body form, the short languets, and the small number of tentacles, are 

 all very characteristic features. The short stalk mentioned above is very slight (PI. 

 XXXIV. fig. 7), and is merely the narrowed posterior end of the body. It is not suffi- 

 cient to affect the general statement that the body is sessile in Ciona. 



The musculature of the mantle is not very strong, but takes the form of longitudinal 

 bands so characteristic of the genus. 



The branchial sac, when first opened, showed the contracted and irregularly crumpled 

 condition so frequently seen in spirit specimens of Ciona intestinalis, ami caused by the 

 pressure of the strongly contracted mantle lying over it. 



(ZOOL. CHALL. EXP. — PAET XVII. — 1882.) E 31 



