6 M. FOSLIE. FIVE NEW CALCAREOUS ALGÆ. [1900 No. 3] 



The conceptacles of sporangia nearly agree with those in L. 

 amplexifrons, however especially in f. mediocris at first slightly 

 raised above the surface of the frond. It also much approaches 

 young specimens of the said species in habit. However, on a 

 section the cells are shown to be much smaller, and seldom verti- 

 cally elongated as frequently in the latter species. 



The species is know from the pacific coast of middle Japan, 

 Marine Laboratory at Sagami province, f. tenuis, and from Santa 

 Cruz, California, f. mediocris. K. Yen do and Dr. Anderson. 



Melobesia (Heteroderma) canescens Fosl. mscr. 



Thallus forming suborbicular, at length confluent and irregular, 

 rather extended crusts on Paclina arborescens. In a young stage 

 the colour is a pale rosy, older greyish or greyish-green. The 

 crust attains a thickness of at least 120 ,u, with more layers of 

 cells. The basal cells are frequently several times longer than 

 broad, or 25 — 60 fi in height, the upper shorter or often nearly 

 square. 



The conceptacles of sporangia are somewhat crovvded, sub- 

 conical, but not distinctly marked, 300 — 350 <j- in diameter seen 

 from above. The sporangia are four-parted, 45— oO /j. long and 

 25—30 fx broad. 



This species apparently stands nearest to Melobesia coronata 

 Rosan. Rech. Melob. p. 64. I should even be inclined to consider 

 it but a form of the latter, supposing that the specimen which 

 underlies the description 1. c. has been a young one. However, 

 for the present it must be regarded a separate species. 



It has been found on the pacific coast of middle Japan, Ma- 

 rine Laboratory at Sagami province, K. Yen do. 



