38 



portion. PL 9, fig. 1 represents a specimen which is hollow, but 

 has not yet opened itself, and fig. 3 a younger specimen nearly 

 covering the one half of a muscle (Myttlus modiolus). The other 

 (lower) half not visible in the figure is in part covered with L. 

 dela/psum described below, and both species grow over an earlier 

 founded specimen of L. Stromfeltii. Hollow, or in the lower side 

 opened or cup-shaped specimens are here much rubbed and the 

 interwalls between the branch-systems visible. The subdichoto- 

 mously divided branches are short, with axes of at least two 

 orders, probably more, but the lower have always disappeared in 

 older specimens. They are terete or nearly terete, erect, fastigiate 

 and straight, 3 — 5 mm. thick, frequently slightly enlarged towards 

 the apex, seldom slightly tapering with rounded ends, most often 

 obtuse and occasionally truncate or nearly truncate. The branches 

 are more or less anastomosing, always in their lower part, but 

 often also farther up and nearly to the apex, at or below the latter 

 now and then provided with wart-like processes. 



There is a considerable difference in general appearance be- 

 tween typically developed specimens with the tip of the branches 

 obtuse or rounded and those, in which the apex is truncate and 

 even rather disc-shaped. Cp. pi. 9, fig. 4. This appears, however, 

 to be caused by local relations, the part of the plant turning to- 

 wards the bottom, or other branches of such specimens showing 

 a typical development without any limit at all. I, therefore, do 

 not record this form a separate and named one. 



The named form as well as the typical also develops freely 

 on the bottom. In this case it is branched from the centre, the 

 branches more or less anastomosing especially outwards, and it 

 also then gets hollow and at length cup-shaped, but apparently in 

 a later stage than if surrounding other objects, or keeping a spherical 

 shape for a longer time, if too much attacked by boring-muscles. 

 PI. 9, fig 2. 



With regard to structure both forms agree with one another. 

 The inner cells of a section parallel with the longitudinal axis of 

 a branch are nearly squarish or rectangular, frequently about 10 

 {J. long and 6 jx thick, or a little shorter in proportion to the thickness 



