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



band. The eudostyle extends from between the second and third to between the fourth 

 and fifth muscle bands, and so occupies about two intermu.scular .spaces (PL III. fig. 3). 



Doliolum challengeri, n. sp. (PI. III. fig. 4). 



Body of the usual cask-like form. 



Mantle having the usual eight muscle bands. 



Branchial Sac well developed. Stigmata numerous. The dorsal series commences 

 at the second muscle band, and extends back to the fifth. Ventrally the stigmata end 

 anteriorly at the third muscle band. 



Endostylc reaching from the second to the fourth muscle band. 



Intestine curved, with the convexity ventral. 



I place in this new species the following sj^ecimens from the Challenger collection : — 



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

 specimens. 



(?) (2.) June 17, 1875 ; Station 237, North Pacific ; .surface ; lat. 34° 37' 0" N., long. 

 140° 32' 0" E. ; surf. temp. 73°; twelve specimens. 



(3.) June 18, 1875 ; Station 238, North Pacific; surface ; lat. 35° 18' 0" N., long. 

 144° 8' 0" E. ; surf. temp. 70° "5 ; two specimens. 



(4.) June 19, 1875; Station 239, North Pacific; surface; lat. 35° 18' 0" N., long. 

 147° 9' 0" E. ; surf. temp. 70° "2 ; three specimens. 



(?) (5.) June 24, 1875 ; Station 242, North Pacific ; surface ; lat. 35° 29' 0" N., long. 

 161° 52' 0" E ; surf. temp. 68°'5 ; three specimens. 



(?) (6). April 13, 1876 ; Station 352, off" the AVest Coast of Africa; surface ; lat. 10° 

 55' 0" N., long. 17° 46' 0" W. ; surf temp. 77°"7 ; one large and three small specimens. 



This species is closely allied to Doliolum denticulatum. The specimens from the 

 North Pacific, collected on June 17, 18, and 19, 1875, are all mounted as microscopic 

 objects. The nerve ganglion is placed in front of the fourth muscle band, but close 

 to it. 



In the specimens from near Fiji, August 11-12, 1874, the testis is long, and extends 

 forward to the thii-d muscle band. The alimentary canal is placed between the fifth 

 and the seventh muscles. 



The specimens collected on June 17 and 24, 1875, and on April 13, 1876, differ 

 slightly from the others. In those of June 24, the stigmata of the dorsal series 

 commence at the third muscle band, as in Doliolum tritonis, in place of at the second. 



The specimens from the Atlantic, collected on April 13, 1876, are on two slides 

 mounted as microscopic objects. The stigmata extend forwards dorsally to the second 

 muscle band, but very little structure beyond that can be made out from the 

 specimens. 



