REPORT ON THE TUNICATA. 35 



colony the four terminal Ascidiozooids are very distinct, and form a row by tliemsclves 

 (PL II. fig. 8, 1, 2, 3, 4). This was given by Lesueur as one of the characters of his spccdes 

 Pyrosoma elegans, but Savigny declares that with care it may be made out in specimens of 

 Pyrosoma giganteum also. I have never seen it so distinct as in the present specimen. 



In the other three colonies the Ascidiozooids are not so prominent as in the case of 

 the specimen just described, but here and there one is found on a conical eminence, 

 or forming a projection on the surface ; so they probably all belong to one species, 

 and sj)ecimen B is more inflated than the other three. lu all these colonies, but 

 especially in C and D, the Ascidiozooids are arranged with regularity in transverse rows. 

 There are from seven to nine rows in each colony, and the rows are most closely placed 

 at the open end of the colony, where also all the young Ascidiozooids are situated. 

 This arrangement of the Ascidiozooids of the colony in regular series or verticils is the 

 chief character distinguishing Pyrosoma elegans, Lesueur, from the other species, and 

 possibly these colonies may be young specimens of that species. On the other hand, 

 the regularity of arrangement may merely be due to the fact that they are still fairly 

 young colonies in which there has not yet been time for the Ascidiozooids to l^econK; 

 irregularly scattered. 



(8.) A small colony, from Station 170, July 14, 1874 ; lat. 29° 55' 0" S., long. 178' 

 14' 0" W. ; 520 fathoms; surf. temp. 65°, bottom temp. 43°, is in such a bad state of 

 preservation that nothing can be made out from it except that it is a Pyrosoma. It is 

 1 cm. in length and about 6 mm. in greatest breadth. 



(9.) A small colony collected on the surface of the Pacific Ocean on April 5, 1875 ; 

 Station 280 ; lat. 26° 29' 0" N., long. 137° 57' 0" E. ; surf. temp. 68°-5, resembles 

 specimen B, described above under (7), and may also possibly be referable to Pyrosoma 

 elegans, Lesueur. It, however, consists of the test of the colony only ; the Ascidiozooids 

 have entirely disappeared, although the projections they formed on the surface of the 

 colony are still visible. Probably the specimen was a dead and decayed one when 

 collected. It measures 1'3 cm. in length and 10 cm. in greatest breadth. The common 

 cloacal aperture is exceedingly small, being only 1 mm. across. 



(10.) Two young colonies were collected on the surface of the Pacific in March 

 1875. They were mounted as microscopic objects during the expedition, and have 

 become so transparent that almost nothing can be made out in them. The one is 

 1 mm. and the other 2 mm. in diameter. The smaller has four Ascidiozooids only. 

 The larger appears to have more, but I cannot make them out with any certainty. 



(11.) A young colony was collected on the surface of the Atlantic on April 13, 

 1876 ; Station 352 ; lat. 10° 55' 0" K, long. 17° 46' 0" W. ; surf. temp. l?"'?. It had 

 been mounted like the last specimens, but fortunately was stained in carmine first. 

 This colony is apparently slightly older than the one obtained on April 12, 1876, and 

 described above (No. 1). It is nearly 2 mm. in thickness, and has four Ascidiozooids ; 

 the tentacles are, however, all developed. 



