GEAF ZU SOLMS-LAUBACH— MONOGliAPll OF THE ACETAIiULAJUl-LE. ;U 



ray a small number of spores are formed, distinguished hy their very strongly calcified 

 membranes; spore-membrane stratified, with a definite lid ; calcification of the axis only 

 in the outer layers, forming irregular warty flakes consisting exclusively of carbonate 

 of lime ; the pod-shaped sporaugial rays are also covered externally with a thin areolated 

 incrustation of lime. 



Whether repeated diaphysis occurs in this genus as in other calcified Dasj/cladacecc I 

 cannot definitely say, since I have been unable to obtain the very young plants on \\ hich 

 alone this could be determined. As soon as the plant once fructifies, it appears then to 

 have reached the end of its development. On a specimen of //. spicata examined with 

 this view an active grooving point was no longer present, and above the last fertile 

 whorl, which, like the next, contained small spores, the axis ended in a flat surface with 

 thickish walls. In the copiously branched basal portion there was no protoplasm to be 

 found to indicate the probability of a new shoot. 



1. Halicortne Wrightii, Harv. in Proc. Amer. Acad. iv. p. 333 (1859). Verticilli 



steriles horizontales, deraum deflexi. Radii fertiles sporas liberas continentes, 

 membrana crasse incrustata instructas. 



Sporangial rays of the young plant extended at right angles, ultimately drooping 

 backwards along the axis. Sporangia and spores somewhat large, the latter globular, 

 fairly numerous, with very strongly calcified membranes, completely free and in no way 

 united or adhering. 



Size : mature plant 3-4 cm. high ; length of disc-ray with basal portion 2*2 mm. ; of 

 the basal portion 0'18 mm. ; spore diam. 0'18-0-22 mm., of which the thickness of 

 the membrane is 0-02-0*03 mm. ; breadth of lid Oil mm. (Plate IV. figs. 4, 5, 8, 10.) 



Kah. On the Loo-choo Islands, first collected in 1856 by the Prench naval officer 

 Thomas (ins. Nawa), Hb. Thuret ; in the same place by Wright on the muddy shore 

 (Hb. U.S. North Pacific Explor. Exped. no. 13), and described from these specimens by 

 Harvey, Hb. Thuret. At Mactan, Philippines, May 1876, by Moseley (* Challenger * 

 Exped., Hb. Brit. Mus., Hb. Kew.). 



All the specimens of Wright examined by me, and also those of the * Challenger ' Ex- 

 pedition, are young and sterile, and I was able to study the fruits only on those collected 

 by Thomas. Agardh appears, however, to have obtained fertile specimens from Wright's 

 material. His statements are on the whole correct ; he found the small hair-protuberances 

 on the sporangial rays as well as the traces of the alternating hair-whorls. The 

 calcification of the spore-membrane has escaped his notice. 



2. Halicoryne SPICATA, Kiitz. Verticilli steriles sursum convergentes. Radiorum ferti- 



lium sporse in massulam irregularem conglobatge, membranis incrustatis instructs?. 



Sterile sporangial rays of the young plant, erect, converging, the fully gro\^Ti ones not 

 much more than half the length of those of the preceding species; spores few in 

 number and cohering in a mass not quite filling the ray, irregularly polygonal, with 

 strongly calcified membranes. 



Size : length of the disc-ray with basal portion 1*37 mm, ; spore diam, Olo mm. ; 

 thickness of spore-membrane 0022 mm. (Plate IV. figs. 3, 7, 9, 11.) 



