— 20 — 



covering up small extraneous objects partly by scars after emptied concep- 

 tacles being irregularly effaced, or the dropped conceptacles leaving small 

 elevated edges not dissolved. The crust is in f. minuta frequently but 

 30 — 60 // thick, in f. simulans up to about 100 t u thick. 



A vertical section of the crust shows an almost coaxilate develop- 

 ment. The hypothallic cells are frequently rather elongated, up to about 

 25 fi long, sending forth a rather feebly developed perithallic layer. The 

 cells of the latter are partly roundish partly square, 7 — 10// in diameter, 

 however often with the longest diameter now in horizontal now and more 

 frequently in vertical direction, in the latter case exceptionally up to 14 

 long and 7 fi broad. 



The conceptacles of sporangia are scattered or somewhat crowded 

 in any part of the crust except the peripherica] portion, convex, in f. mi- 

 nuta less prominent than in f. simulans, towards maturity sometimes a 

 little flattened in the central parts, in the former 300 — 400 a and in the 

 latter 400 — 500 p. in diameter seen from above. The roof is intersected 

 with about 40 delicate muciferous canals. The sporangia are four-parted 

 in both forms, in f. minuta 60 — 70 fi long and 25 — 30 ti broad, but in 

 f. simulans 140 — 160 p long and 60 — 80 fj. broad. However, this is 

 perhaps not to be considered the average size , as 1 have examined but 

 a couple of conceptacles owing to the scanty material. 



The conceptacles of cystocarps frequently appear in other individuals 

 than those of sporangia. They are conical and, as in other species of 

 this genus , abruptly passing into a very short and thin tip. Also these 

 are smaller in f. minuta than in f. simulans, in the former 350 — 450 p. 

 in diameter at the base and in the latter 500 — 600 p. 



Both forms are provided with the said organs in February, carpo- 

 spores however more scarce than sporangia. 



I have been in doubt whether f. simulans ought not perhaps to be 

 considered as a separate species, but as I have seen only a solitary well 

 developed specimen of this form I do not hesitate to keep it distinct, 

 especially since the material also of f. minuta is scarce and some of the 

 specimens no doubt are somewhat stunted. Nor have 1 been able to 

 draw any true limit , setting aside the proportionally large reproductive 

 organs in the former. But also in other species a great difference as 

 regards the conceptacles sometimes is to be seen, for inst. in Lithotham- 

 nion laevé. The forms have been found under different conditions which 

 not unlikely have had some influence on their development such as for 



• instance in the said species as well as L. Lenormandi. 



The present species stands nearest to L. Lenormandi and reminds 

 one in habit of young specimens of f. sublaevis. It approaches this form 

 also as regards the conceptacles of sporangia, while those of cystocarps 

 are different. 



II naut. miles NW. of Koh Kam on a depth of 10 fathoms (f. minuta): 

 between Koh Mesan and Cape Liant, 9 fathoms (f. minuta) ; 15 naut. miles E. 

 of Koh Ghuen, 10 fathoms (f. minuta'?); between Koh Mesan and Koh Chuen, 

 15 fathoms (f. minuta); the north side of Koh Mesan in 10—15 fathoms water 

 (f. minuta); and Koh Sarlak, on Septifer bilocularis L. in shallow water (f. si- 

 mulans), — almost, everywhere in solitary individuals. 



