THE "TRITON" TUNICATA. Ill 



and, after a short undulating course as a very fine tubule, enlarges into a 

 pear-shaped dilatation extending to the 2nd muscle band. In fig. 9, which 

 is drawn on a larger scale, there are two dilatations on the narrow part of the 

 tube, while in fig. 11 the narrow part is long and convoluted, and extends 

 forward to the 2nd muscle band. In fig. 10 the testis reaches the 2nd 

 muscle band without any diminution in its calibre, and then, narrowing slightly, 

 forms a loop extending almost to the 1st band, after which it curves back to 

 wards the 2nd, and ends in a narrow filament. The two remaining cases figured 

 are the most remarkable of all. In fig. 8 the tube narrows rapidly opposite 

 the 3rd muscle band, and from this point forwards almost to the 1st it remains 

 very narrow, but with two large ovate dilatations and several smaller ones upon 

 its course. Fig. 7 shows a case where the wider tube extends to the 2nd 

 band and then suddenly narrows, but the fine tubule, in place of running 

 forwards, turns posteriorly, and eventually reaches the 4th muscle band after 

 passing through several irregular dilatations. Throughout, this male system 

 was filled with minute granular cells (PI. XX. fig. 12), but no distinct sper- 

 matozoa could be made out. 



The most remarkable feature of this " Triton " collection of Doliolidoe is, that 

 such vast numbers should prove to be entirely one generation of the same 

 species, and all, with a very few exceptions, of much the same size. Questions 

 naturally arise such as, Where have they come from ? Where are the asexual 

 forms from which they have been produced % and Why are such quantities of 

 that species found in that locality at that time ? We are not yet in a position 

 to answer any of these questions fully. Mr Murray tells me that when 

 captured, they were all drifting from the south-west to the north-east. This 

 would carry them from the " warm area " across the " Wyville-Thomson " ridge 

 into the " cold area," but what part of the Atlantic they came from, or how far 

 north they are carried, is not known. Mr Murray states that "they were 

 abundant during the whole time of the cruise, except when we touched upon 

 the Faroe bank water." As far as I can judge from the numbers of specimens 

 in the tubes collected on the different days, the configuration of the bottom 

 and the division of the region explored into " warm " and " cold " areas has 

 no effect whatever upon the abundance of the Doliolidse. There are large 

 quantities of specimens in the collection from the 3rd to the 5th August, 

 halfway between Kona Island and the south-east end of the ridge ; on the 29th 

 August, over the centre of the ridge ; on the 28th and 31st August, in the 

 " warm area ; " and on 20th to 23rd August, in the " cold area." The region 

 from which the smallest numbers have been brought back are those explored 

 on the 7th to the 9th August at the north-west extremity of the ridge. 



Mr Murray has kindly supplied me with the following extracts from his 



