62 University of California Publications. Izoology. 



tubular, somewhat broader than hydrotheeae and five to six times as long as 

 broad. A single tubular gonophore. 



Distribution. San Diego Bay, Cal., 5-12 fathoms. 



The everted margin, with its frequent reduplication in old 

 hydrotheeae, suggests the Haleciidae. The remarkable position 

 of the gonophores is characteristic of Allmau's genus Syntheciwm. 

 This genus is to my mind untenable, since it wrenches from their 

 nearest allies such diverse species as Sertularella alterndns and 

 Sertularia campylocarpwm and unites them on the basis of a 

 feature which is chiefly interesting to the physiologist. It has 

 doubtless arisen independently in several species, and cannot at 

 most have more than specific value. It is significant that the 

 species just named were taken in the same haul of the dredge and 

 were thus presumably surrounded by similar conditions. To make 

 manifest the importance of a physiological point of view in this 

 connection, the fact might be recalled that in the genus Obeli a an 

 axillary bud may grow into either a blastostyle or a hydranth, 

 the function being determined by physiological conditions operat- 

 ing after the bud has begun to grow. 



The male gonosome develops, briefly, as follows: A hydranth 

 degenerates. From its more or less disorganized tissue at the 

 base of the theca a bud springs, with no sign of definitive sex 

 cells in or near it. When this bud attains about twice the length 

 of the hydrotheca, sex cells appear between the ectoderm and 

 endoderm, in a region varying in length, extending from near the 

 tip over the distal half of the bud. There is no sign of orifice in the 

 covering of perisarc which has been secreted over the growing bud. 

 The bud stalk does not behave as a blastostyle, since no secondary 

 buds are produced; it alone functions as the gonophore. Full 

 maturity has not been reached by any of these structures in the 

 scant material at hand, but at this stage they bear a striking 

 resemblance to the sporosacs among the Gymnoblastea. They 

 may arise from any hydrotheca. The maturest may be distal or 

 proximal to the others; the usual order of succession from base 

 to tip of the colony is not observed. 



The cause which determines the formation of a gonophore out 

 of the substance of a degenerated hydranth in 8. halecina is as 

 mvsterious as that which determines whether a certain bud in an 



