

was ih.it nearer the ventral line. Similarly, owing ti> the shortness of these mesenteries their 

 idual diminution in successive quartettes was not very pronounced. 



\ 'k the macrocnemes, there is a great disparity in the lengths ol the shorter 



and longer ones, the former extending bul a 

 short distance below the lower border of the 

 stomatodaeum, while the latter reach at l< 

 as far as the middle of the column, some oi 

 them almost to the aboral pole. Nor is the 

 ventro-dorsal diminution of the longer macro 

 cnemes a constant one. In four individuals 

 examined the longer macrocneme of the first 

 < jnartette reached a little beyond the middle 

 of the column, that of the second quartette 

 almost to the aboral pole, that of the third 

 to about the lower fifth of the column, and 

 that of the fourth almost to the aboral pole. 

 Beyond this some variation occurred, the lo 

 mesenteries of the fifth and sixth quartettes 

 reaching to beyond the middle of the column, 

 that of the sixth being usually, but not always, 

 slightly the longer of the two, and then foliowed 

 sometimes one, and sometimes two quartettes 

 in which the mesenteries under consideration 

 almost reached the aboral pole, and in the 

 remaining three or tour quartettes they rapidly 

 diminished in length. 



In all the forms hitherto described the 



alternation of sterile and fertile mesenteries is 



characteristic of the quartettes, but in a form 



found in the "Siboera" collection and which I 



identify with C. ambonensis this was not the 



-e, all the mesenteries. both protocnemes 



and deuterocnemes, being fertile with the exception of the directive couple. A detailed account 



of this form will be given later on and it need merely be stated here that the deuterocnemes 



were arranged in two alternating the brachycnemes extending only to about 3 cm. below 



the lower border of the stomatodaeum, while the macrocnemes were continued onwards for 



5 cm., reaching to within 2 cm., of the aboral pole, the telocnemes, which are the 



eing the only mesenteries to reach that pole. Whether slight variations in length 



of ti rocneme each, or even of successive quartettes, wen- always presenl I was unable 



the arrangement of the deuterocnemes appearing to be in duettes rather than in 



quarti tl figure V, p. 2 



16 



IV. 

 g the arrangement of the mesenteries of 



