REPORT ON THE TUNICATA. 45 



Philosophical Transactions for 1851, and it is to that account we must go for informa- 

 tion as to the characters of the present species. 



Huxley represents the branchial aperture as surrounded l)y about nine rounded 

 denticulations, while the atrial has a larger number of narrower and more pointed 

 processes. The endostyle commences anteriorly a little behind the second muscle 

 band, and extends back nearly to the fourth.^ The stigmata of the In-anchial sac 

 commence dorsally a little in front of the second muscle band, and extend back to 

 about the sixth ; they then reach forwards ventrally as far as the third muscle Itand, 

 thus overlapping the posterior half of the endostyle. The alimentary canal forms a 

 V-shaped loop between the fifth and seventh muscle bands. The intestine appears to 

 curve dorsally, anteriorly, and to the right."^ The testis is long and narrow ; it lies on 

 the left side ventrally, and extends anteriorly nearly as far as the first muscle l)and. 

 The dorsal tubercle and the spirals of the peripharyngeal bands are placed Ijetwcen 

 the first and second muscle bands. These are the more important characters of this 

 species which can be made out from the description and figures given Ijy Huxley. 



Although several authors since 1851 have described specimens under the name of 

 Doliolum denticulatum, yet a careful examination of their figures and descriptions 

 shows that they all refer to species other than the true Doliolum denticulatum. 

 Krolm's Doliolum denticidatum, for which he also proposed the name ehrenhergii, 

 is not the same as Huxley's, and therefore becomes the type of the new species 

 Doliolum ehrenhergi. The Doliolum denticulatum of Keferstein and Ehlers was 

 probably, as Uljanin points out, ^vo\vci?, Doliolum ehrenbergii ; and Grobben's Doliolum 

 denticulatum was probably also the same species. The species found by the " Triton " 

 Expedition in the North Atlantic in 1882, and which I referred at the time with some 

 hesitation to Doliolum denticidatum, is, I now consider, not that species. Consec^uently 

 the true Doliolum denticulatum has apparently not been recorded since Huxley's paper 

 was published in 1851. 



During the Challenger Expedition the following specimens were collected which I 

 refer to this species : — 



(1.) August 11-12, 1874; ofi" Kandavu, Fiji; surface; surf temp. 77°'5 ; one 

 specimen, 4 mm. long, 3 mm. broad. 



(2.) April 2, 1874 ; Station 1G2, ofli" East Moncoeur Island, Bass Strait; lat. .39° 10' 

 30" S., long. 146° 37' 0" E. ; surface ; surf temp. 63°'2 ; two rather narrow specimens (?), 

 5 mm. long, 2 mm. broad. 



(3.) April 11, 1876; Station 350, tropical Atlantic, lat. 7° 33' 0" K, long. 15' IG' 

 0" W. ; surflice ; surf temp. 84° ; six small rather narrow specimens (?). 



(4.) April 29, 1876 ; tropical Atlantic, lat. 18° 8' 0" N., long. 30° 5' 0" W. ; suifice ; 

 surf temp. 74° ; one small specimen. 



' I number the muscle bands one to eight consecutively, beginning .it the branchial aperture. Huxley does not 

 count the first and eighth, and numbers the others one to six, consequently his third is my fourth. 



- In reading Huxley's description it is necessary to remember that he called the dorsal surface ventral and the 

 ventral dorsal. The right and left sides must also be reversed. 



