W. H. HARRIS ON MARINE MICROSCOPIC VEGETABLE ORGANISMS. 153 



Of the geological distribution of these organisms I have little 

 information worth recording. They are plentiful in material 

 from the Miocene deposits of the west coast of New Zealand, 

 Belgium, and France ; also in Calcare grossier material belonging 

 to the Middle Eocene period. In a slice of carboniferous lime- 

 stone taken from the Polyzoa bed at Clifton, Bristol, I have 

 detected two short fragments of filaments which closely resemble 

 the organism known as Saprolegnia, beyond which I liave no 

 further record. 



Co7iclusion. 



Although no one can be more conscious of the many imper- 

 fections and shortcomings of this paper than myself, still 1 

 sincerely hope some allowance will be made on account of the 

 many difficulties the subject presents — difficulties to be thoroughly 

 understood and duly appreciated only when real work is attempted. 



If I have been instrumental in making any addition to the 

 general knowledge of the subject, or other workers are thereby 

 induced to take up the study of these interesting organisms, I 

 shall conclude that my work has not been undertaken in vain. 



Descriptions of Species. 

 Genus Lacuna. 



Lacnna fstnlom.. — A small irregular-shaped species, occupying the super- 

 ficial layers of the fragment ; the portion of cavity nearer the surface is beset 

 with numerous short, stout, tubular processes, which reach the surface of 

 the containing fragment ; sometimes tolerably large portions of shell arc 

 eroded, exposing the under side of the organism. 



They occur as isolated individuals, and are rare. 



My specimens were obtained from Cebu, Philippine Islands, 20 fathom?, 

 and Auckland, N.Z., littoral deposit. Plate 9, Fig. 1 x 280. 



Lacuna pntescejis. — This is a robust flask-like form, thickly beset with 

 moderately long appendages, which give the organism a hairy or fleecy 

 appearance. 



There are one or two rather long filamentous processes given off from the 

 bulbous portion in my examples adorned in a similar manner, but until 

 further specimens can be- found from other localities this cannot be stated to 

 be a constant feature. 



Mr. Waller informs me he had met with this species and had sketched it, 

 but did not name it or describe it. 



Undoubtedly it is a rather rare form ; the only specimens met with by me 

 were found in material from Java Sea and Macassar Straits, both 45 fathoms 



