148 



H. B. TORREY. 



Table VIII. 



Measurements in mm. X 95- 



just preceding, it aids in establishing the fact that colonies of A. 

 plimia, like colonies of A. octocarpa, have a limited growth and a 

 specific form, the hydrocladia, with respect to given characters, 

 differing in different regions. To appreciate this fact, it is only- 

 necessary to note the position (i) of the maxima on the various 

 hydrocladia in Tables V. (upper figures), VII. and VIII., and 

 (2) of the minima in Table VI., especially in connection with 

 hydrocladia 5, 13, 21, 23 and 24. 



A. inconspiciia} — This small species is represented most scantily 

 in the collections of the University of California. No conclusions 

 can be offered concerning the form of the colony as a whole, as 

 observations on the tip of a mature colony are at present out of 

 the question. From the drawings (Fig. 3) of the internodes from 

 two hydrocladia, however, and the measurements based upon 

 them. Tables IX. and X., the species possesses admirable char- 

 acters for experimental work, in the prominence of the mesial 

 nematophore and the obliqueness of the hydrothecal opening. 



These figures are typical, similar measurements from other 

 hydrocladia and other colonies giving results that vary, within 

 the hydrocladium, in no essential respect from them. It may be 

 said that the hydrotheca at the base of each hydrocladium is 

 especially variable and often differs conspicuously from those 

 distal to it in size, shape, marginal dentation, and position on the 



^Torrey, Univ. Cal. Publ., Zool. , I, 1902; ibid., 2, 1904. 



