REPORT ON THE TUNICATA. 43 



(l.) Doliolum mulleri, Krohn. 



(2.) Doliolum i-arum, Grobben. 



(3.) Doliolum ehrenhergi, Krolm. 



(4.) Doliolum gegcnbauri, Uljanin. 



The last-named species is (according to Uljanin) tlie Doliolum denticulatum of 

 Huxley, while Doliolum denticulatum and Doliolum caudatum of Quoy and Gaimard 

 are regarded as doubtful species which cannot be identified. As I have already 

 explained above (p. 39), if Quoy and Gaimard's species are to be given up as unre- 

 cognisable and pass out of the literature of science, then Huxley's name, Doliolum 

 denticidatum, has priority over Uljanin's ; but I prefer to regard Huxley's species and 

 Quoy and Gaimard's as identical. In either of these cases Doliolum, gegenhauri would 

 laj^se as being an unnecessary synonym. A careful comparison, however, of the 

 description and figures of Huxley with those of Uljanin does not support the identity of 

 the two species insisted on by the latter author, and the branchial sacs certainly have 

 very different relations in the two forms. Consequently ib may be right to retain the 

 specific name gegenhauri for the new Mediterranean species described by Uljanin, and 

 having the arrangement of stigmata shown in PI. HI. fig. 2. 



During the cruise of H.M.S. "Triton" in the summer of 1882 in the North 

 Atlantic, Dr. John Murray captured in the tow-net vast numbers (thousands were 

 preserved) of a Doliolum in the reproductive stage, which I described fuUy,^- and 

 identified doubtfully with Doliolum dentimdatum, Quoy and Gaimard, after pointing 

 out the diflferences existing between the "Triton " specimens and the species described 

 as Doliolum denticidatum by Huxley and by Keferstein -and Ehlers. I have now no 

 doubt that Keferstein and Ehlers' species was distinct from Huxley's, and I am inclined 

 to regard the " Triton " specimens as belonging to a third species, distinct from both 

 the others, which may be appropriately named Doliolum tritonis. 



The Challenger collection contains specimens of three species which appear to be 

 different from any previously described. Of these, two are closely related, and are 

 evidently not far distant from Doliolum ehrenhergi ; while the third is very difi"erent, 

 and belongs to the group of species with comparatively few stigmata containing 

 Doliolum varum and Doliolum mulleri. 



Altogether, then, nine species of the genus may now be distinguished : — 



Doliolum denticidatum, Q. and G. (and Huxley). 



Doliolum ehrenhergi, Krohn. 



Doliolum gegenhauri, Uljanin. 



Doliolum tritonis, Herdman. 



Doliolum ciffine, n. sp. 



Doliolum challengeri, n. sp. 



Doliolum mulleri, Krohn. 



' Ilcport on the "Triton" Tunicata, Trart?. Roy. Soc. Ediii., vol. x.\xii. part i. p. 90, 1883. 



