278 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



D. 138, dredged in 30 m., south of Tiburon Island, near Turner's 

 Island, Jan. ; D. 347, in 22 m., off Punta Penasco, Feb. 



This species is distinct from Halymenia abyssicola of this paper in its 

 thinner fronds ( 70-130 /x) , outer cortex of only one or two layers of small 

 cells, and absence of a thick surface jelly. 



Halymenia ? abyssicola sp. nov. 



Frondes planae membranaceae, minime 8 cm. latae, 300 \i, crassae, raarginibus 

 integris, atro-roseae; glutino superficiali 25-35 ^ crasso; corticibus stratis paucis 

 cellularum minutarum dense aggregatarum, 5-7 \i diam. compositis; subcorticibus 

 cellulis majoribus compositis; in medulla filamentis laxe intricatis et crabro con- 

 junctiones stellae-formantes ostendentibus ; (frondibus fructuosis nondura visis). 



Fronds plane, membranous, basal parts unknown, at least 8 cm. broad, 

 with an entire margin, 300 )u, thick, deep rose colored ; cross section show- 

 ing a thick surface jelly 25-35 /* thick, a cortical tissue of a few layers of 

 minute, closely packed cells 5-7 /x diam., a subcortex of larger cells merg- 

 ing into a medulla of loosely interwoven filaments with frequent stellate 

 "ganglia" or points of junction. 



Type : D. 433, dredged in 1 10-152 m. off Isla Partida, Feb. 5, 1940. 

 Herb. AHF no. 28. 



The present species is known only from the single collection of frag- 

 mentary fronds which came up from a great depth together with a 

 dredge load of boulders. The thickness of the frond and the presence of 

 the thick surface jelly seen in cross section make it distinct, however, from 

 any known broad, plane, entire-margined species. Furthermore, its occur- 

 rence at such great depths is remarkable, and it seems well to put it on 

 record for the information of future collectors. The cross-sectional struc- 

 ture exhibits characters corresponding most closely to those generally rec- 

 ognized for the genus Halymenia, but this arrangement can only be tenta- 

 tive until more ample material is available. 



Halymenia ? refugiensis sp. nov. 

 Plate 44, Figs. 2, 3. 



Frondes planae, membranaceae, obtuse lanceolatae, usque ad minime 11 cm. 

 altae, 2.5 cm. latae, inferne gradatim ad bases angustas attenuatae, marginibus 

 integris; corticibus unistratosis cellulis plus minusve complanatis, 4-10 \i in diam. 

 max. compositis; subcorticibus 2 stratosis, cellulis complanatis 15-20 \x longis com- 

 positis et textis internis fila pluricellularia, 6-8 \i diam., transverse et plus minusve 

 et directe usque ad cellulas subcorticales oppositae currentia emittentibus, textum 

 medullarem filorum plerumque simplicum formantibus, filis stricte in longitudinem 

 nullis; (frondibus fructuosis nondum visis). 



