594 PEor. w. A. herdman's eevised 



r Body 4 or 6 times longer than broad. 

 42 \ A. elongata, Eoule. (Med.) 



( Body not much longer than broad 43 



^q / Appearance porcelain-like 44 



* [Not porcelain-like 45 



{Mantle blue, test cartilaginous and smooth. 

 A. arachnoidea, Forb. (Med. & N.W. Eur.) 

 Mantle milk-white, test warty and fibrous. 

 A. ingeria, Trauet. (Med.) 



f Stigmata 1 large and 2 small, or 4 small in a mesh. 

 45 j A.kuneides,B\. (Mai.) 



[ Stigmata not so arranged 46 



(Test containing a remarkable abundance of branched vessels. 

 A. reptans*, Heller. (Med.) 

 Test with no remarkable development of vessels 47 



Af, /Dorsal tubercle horseshoe-shaped 48 



I Dorsal tubercle not horseshoe-shaped 49 



(Apertures far apart, test thickish, dorsal tubercle romided. 

 A. depressiuscula, Heller. (Ind. O.) 

 Apertures not far apart, test not thick, dorsal tubercle cordate. 

 A. obliqua t. Aid. (N. W. Eur. & Med.) 



AQ r Branchial sac with intermediate papillte 50 



I Branchial sac with no intermediate papillie 51 



C Stigmata short, 4 or 5 in a mesh. 

 -„ J A. deprcssa, Aid. (N.W. Eur., ? Med.) 



'1' 



Stigmata long, 10 in a mesh. 



A. koreana, Traust. (Pac.) 



f--, ( Transverse vessels of 3 sizes 52 



[ Transverse vessels not of 3 sizes 53 



{Body thrice as long as broad, siphons very long. 

 A. longitubis, Traust. (W. Ind.) 

 Body almost as broad as long, siphons not very long. 

 ^.p?<si7fo, Traust. (Med.) 



fTest rather thick and smooth 54 



53 \ Test rather thin and wrinkled. 



[ A. malaca, Traust. (Med.) 



{Colour yellow-grey, tentacles 40-50. 

 A. interrupta, Heller. (W. Ind.) 

 Colour milk-white, tentacles 60-70. 

 A. hygomiana, Traust. (W. Ind.) 



The following species of Ascidia J are not suflB.ciently charac- 

 terized to be put in the table. Some are probably synonyms 

 of well-known species, others may be distinct species, but require 

 further examination and redescription ; a few probably do not 

 belong to this genus : — 



* A. vasculosa, Herdm. (from Kerguelen), has also numerous vessels in the 

 test, but as only the test is known I have excluded, the species. 



t A.pellucida, Aid. & Hanc, comes close to this, and as no details are known 

 in regard to its internal structure it cannot be separated from A. obliqua. 



X Wagner's Hyalosoma singulare, from the White Sea (not Hyalonema, as 

 misquoted by Traustedt), seems to me to be merely a young specimen of an 

 Ascidia. 



