164 GRATELOUPIACEAE 
“Dredged in about five fathoms," Bay of Sechura, April 8, 
1907, Coker 157 p.p.,—a single tetrasporic plant, without the base. 
The external characters of this plant, combined with the ре- | 
culiar large gangliiferous filaments that run through the medulla, Е 
will, we think, suffice for Из recognition when it is met with again. E. 
Тһе contents of these large filaments differ in character from those 
of other parts of the thallus in being more homogeneous and | 
refringent. These filaments are easily visible through the cortex | 
under low magnification by transmitted light, especially when 
dried material is soaked out in water; they form an irrégularly 
anastomosing network, with occasionally irregularly distributed 
3-6-pronged nodes or ganglia. The filaments and their соппес- 
tions may sometimes be traced in this way for 3 or 4 mm. They | 
are sometimes straight and rather rigid, and sometimes sinuous, 
contorted, and irregularly swollen. Оп dissection it is seen that 
they sometimes run for 500 и or more without a septum and that | 
they are often tumid on опе ог both sides of a septum. Itis 
possible that these specialized filaments are to be interpreted a 
representing a rudimentary vascular system. Stellately branched . 
cells are found in the medulla or subcortex of the Mediterranean 
Halymenia dichotoma J. Ag., in the Lower Californian H. actino- | 
bhysa М. A. Howe, and іп a less pronounced fashion in Halymenia | 
Floresia (Clem.) Ag., but in these they are the regular and normal | 
cells of the parts in which they occur, while in Sebdenia heteronema | 
they form specialized ог heteromorphous nerves or ganglia ina 
ground substance of a different character. Specialized medullary 
filaments from stellate ganglia, somewhat similar to those of 
Sebdenia heteronema, though less highly differentiated,* occur in 
the type specimens of Halymenia floridana J. Ag., but typical И. 
floridana differs from the true Halymenias in being less gelatinous 
in having a firmer cortex, and in the coarser more granular proto- 
plasts of the cells of the medulla and subcortex.[ Such specialized 
medullary filaments apparently do not occur either in the type 
species of Halymenia (H. Floresia) or the type species of ЗЕ x 
ИРА 
* Such filaments іп Н. floridana we once erroneously suspected of having some 
thing to do with the production of cystocarps (Bull. Torrey Club 38: 511. 1911). c. 
T The plants distributed as Halymenia floridana іп the Phycotheca Borean 
Americana (no. 749), at least in the copy belonging to the New York Botanical | 
Garden, have a very different structure and are evidently true Halymenias. | 
