REPORT ON THE TUNICATA. 33 



The first buds formed by the original Ascidiozooids of the colony are seen from tliis 

 specimen to lie neither on the ventral nor on the dorsal side of the parents, but at their 

 posterior ends. These first buds, as may be seen from the older colony described below 

 (see PI. II. fig. 7), along with four others, evidently pass as they grow larger to tlie 

 dorsal side of the parent Ascidiozooids, and so form the circle of young Ascidiozooids 

 surrounding the open end of the colony ; while the buds formed later, the third and 

 succeeding series, take up their position on the ventral side of the parent, and become 

 the Ascidiozooids at the closed end of the colony. 



(2.) A very young colony (PI. II. fig. 5), labelled " Surface, South Atlantic," like tlie 

 last cannot be referred to its species because of its immature condition. It measures 

 6 mm. in length and about 5 mm. in breadth. It is nearly solid, the central common 

 cloaca being very small, and its terminal opening also minute. There are sixteen 

 Ascidiozooids arranged with perfect regularity (PL II. fig. 7). Four large ones occupy 

 the middle of the colony, eight smaller are placed round the common cloacal aperture, 

 while four still smaller occupy the closed end of the colony. The large central ones are 

 probably the four original Ascidiozooids formed from the eml^ryo, and they have 

 evidently produced each two Ascidiozooids on their dorsal sides, thus accounting for 

 the eight round the cloacal aperture, and then each one Ascidiozooid on their ventral 

 sides, these being the four small ones at the closed end of the colony. The large 

 Ascidiozooids are short bodied, wide dorso-ventrally, and narrow from side to side. 

 The three rows of Ascidiozooids alternate with one another most regularly. If the 

 colony be so placed that the four large Ascidiozooids point north, south, east, and 

 west, then the four smallest will be north-east, south-east, south-west, and north-west, 

 while the eight others will be, a pair between north and east, a pair between east and 

 south, a pair between south and west, and the last pair between west and north (see 

 PI. II. fig. 6, which represents a diagrammatic view from the closed end of the colony 

 with all the Ascidiozooids shown). 



The surface of the colony is very irregular. The test is raised up to form a number 

 of conical sharp-pointed processes (PL II. figs. 5 and 7). There are a series of these 

 around the common cloacal aperture, and others at regular inteiwals over the surface of 

 the colony. They do not correspond in number or position to the Ascidiozooids, but 

 are placed here and there upon ridges of the test which mark out the surface of 

 the colony into areas, each of which is occupied by an Ascidiozooid. The branchial 

 apertures are therefore placed upon smooth regions of the test (PL II. fig. 7, hi:). 



The large Ascidiozooids are in a condition of active gemmation, each having two or 

 three J^oung buds attached to its stolon. These l^uds look as if they would take uj) 

 their position between their parents and the closed end of the colony. 



(.3.) A small colony obtained off the coast of Africa on August 16, 1873 ; Station 100 ; 

 lat. 7° 1' 0" N., long. 15° 55' 0" AV. ; surf. temp. 79", is probably Pyrosoma atlanticum, 

 Peron, but the characters are not yet well marked. It measures 2 "2 cm. in length and 



(ZOOL. CHALL. EXP. — PART LXXVI. — 1888.) Gggg 5 



