22 " ENDEAVOUR " SCIENTIFIC RESULTS. 



serve as a specific distinction, and accepting my identification of 

 8. divaricate as a form with wide-mouthed gouangia, has 

 practically made the possession of a narrow funnel-shaped lip the 

 prime character of 8. sabdichotoma. My examination of numerous 

 specimens shows that neither of these types of gonangium has 

 any exclusive connection with any particular form of trophosome. 



In considering the trophosome only, and disregarding the 

 unimportant distinctions between regular and irregular ramifica- 

 tion, the varieties may be grouped in two series. In one, which 

 includes the type and var. snbdichotoma, the internodes are long, 

 and the hydrothecre therefore are wide apart, and as a rule 

 (though with many exceptions) in one plane and not very widely 

 divergent laterally. The stem-internodcs commonly bear about 

 three hydrothecfe, and even on the pinna? many of the nodes are 

 indistinct or wholly wanting. In the second group the internodes 

 are more distinct and mostly shorter, and the hydrothecre closer 

 together, their lateral divergence is greater and they are mostly 

 adnate for a less proportion of their length ; they are rarely in 

 the same plane, but the two series are in planes which meet at an 

 angle often as small as 90. The general habit is mostly more 

 bushy and compact than in the first group, but there is no 

 abrupt or considerable gap between the two. 



Proceeding now to consider the differences in the gonosome, 

 which are more important, as the case for the separation of 

 S. subdichotoma rests upon them, we find that the varieties may 

 here again be separated into two series, but not coinciding with 

 the two series as determined by the trophosome. In one group, 

 of which S. divaricata is typical, the aperture of the gonangium is 

 large, with a wide everted lip, more ample in some varieties than 

 in others ; in the other series, which includes S. subdicJtotoma, 

 there is a much smaller orifice with a funnel-shaped lip. In four 

 specimens of the first group the diameter of the orifice ranges 

 from '13 to *19 mm., in four of the second from '044 to "059, 

 while in one form it varies between '074 and '089. This last 

 variety, while obviously approaching S. snbdichotoma, is so far 

 intermediate as to suggest the probability of finding, with further 

 material, a complete range of connecting forms. 



The following is a summary of the characters of the nine 

 different specimens of which I have preparations, accompanied by 

 the average dimensions in millimetres. 



1. S. divaricata, Port Stephens. This is the form which I 

 described as typical in 1884, as it bears the closest resemblance to 

 Busk's description and drawing of any which I have seen. It 

 also agrees well with Hartlaub's account and figures. It has 

 alternate pinnee arranged in the fashion typical of the species, 

 but with many irregularities, and it is often in parts bipinnate. 



