DELESSERIA 137 
at Valparaiso by du Petit-Thouars. In Montagne’s herbarium 
at the Muséum d’Histoire Naturelle of Paris, attached to the same 
sheet with an evidently authentic specimen attributed to Val- 
paraiso, is a pocket inscribed “ A glaophyllum leiphaemum Montag. 
Pérou, d'Orbigny” and containing on mica a small fragment 
which appears to have all of the peculiarities of the accompanying 
Valparaiso specimen, even to the encrusting diatoms, and which 
was, in all probability, detached from it. The species seems not 
to have been met with in Peru by Dr. Coker. 
It was Montagne's final opinion that his Halymenia leiphaemia 
belonged to the genus now currently known аз Nitophyllum, but 
this opinion we are unable to share, chiefly on account of its obvious 
apical cells. The plant, however, bears a certain resemblance to 
the Australian Nitophyllum fallax J. Ag., which, alone, Agardh* 
makes to constitute his “Tribus VII. Costatae” of the subgenus 
Aglaophyllum. The stipe of du Petit-Thouars’ specimen is ellip- 
tic or lenticular in cross-section and is about 0.8 mm. broad and 
0.25 mm. in greatest thickness. Its continuation forms an obvious 
costa in the basal parts of the thallus and faint evidences of the 
presence of a costa may be seen now and then, in the pressed and 
dried specimen, even extending into the terminal lobes, but in 
general the costa becomes broad, diffuse, and scarcely discernible 
except іп a cross section. It often occupies 14-34 the width of 
the segment and sometimes, by the suppression or wearing away 
of the marginal laminae, may constitute the whole width of the 
segment. Тһе costa is mostly 4-6 cells thick, while the alar 
lamina is 1 or 2 cells thick. Тһе superficial cells of the costa are 
of about the same size as subjacent cells, but the medullary axial 
cells of the costa are somewhat enlarged. Тһе superficial cells 
of costa and the cells of the laminae are mostly 25-55 и іп maxi- 
mum length. Тһе thallus margins are commonly erose-crenulate, 
with small blunt irregular teeth. Rarely one may perceive a 
fairly well-defined nerve running from the margin of the costa to 
a marginal tooth. Тһе teeth commonly show protuberant thick- 
walled apical cells, but the adjacent cells do not have the regu- 
larity of arrangement that is characteristic of the typical species 
of Delesseria. However, the young and rarely occurring pro- 
# Sp. Alg. 33: 48. 1898. 
