KONGL. SV. VET. AKADEMIENS HANDUNGAR. BAND 32. N:0 I. 45 



and reach to the centre where thev are united Avith some rests of as vet unchanffed coenen- 

 chjana out of which låter the columella develops. This central part remained isolated 

 as columella, when the septa are shortened to their normal size. The top of the colu- 

 inella, in the large vai'iety of figure 20, as represented in section fig. 22, is divided into 

 tiny spines, else generally smooth. As is evident by many longitudinal sections, tigs. 8, 

 15, 23, the columella has not been formed continually during the whole life of the 

 polyp, its growth has been interrupted and continued aneAv (figs. 2, 8). It can be followed 

 as a long whitish line in the centre of the calicular tnbe (fig. 15) and then again ceases. 

 In fig. 2 it has a peculiar appearance, disconnected on two of the lowest tabulje and again 

 reappearing on one of the uppermost. 



Tahulce. They are in the rule horizontal, four on a length of one millim. They 

 occur densely crowded near the top of the calicular tube (figs. 22 — 23) as to form large 

 horizontal bands. This must depend on some abnormity, on an excessive or sickly secre- 

 tion, an accelerated growth. Near the theca the tabula^ are sometimes wavy or provided with 

 a sort of grooves, especially where they meet the septa (fig. 29). These remind a little 

 of those which are seen in several species of Favosites and may have the same sort of 

 origin as these but do not occur regularly. 



Coenenchyma. The tubes of the coenenchyma are in the rule polygonal, five or 

 six-sided, the dividing walls thick, as in specimen fig. 9, or threadfine as in fig. 20. The 

 line which divides the walls of two contiguous tubes, can be discerned in specimens as 

 fig. 9 and 13. There are closely set, regularly horizontal tabulas, five on a length of one 

 millim. or even more. The tubes augment by fission. A small partition wall grows out 

 from the wall into the tube (many instances fig. 20), meets a similar from the opposite 

 side (f. 13) or even four meet (f. 9) and form like ;i Tetradium four new tubes. In the 

 coenenchyma between the second and third calicular tube at left in fig. 31 there is at first 

 a single coenenchymal tube, which divides into two, and these again at a short distance 

 again in two, so that four new have been produced out of one. 



At times there has been a singular invasion of the coenenchyma över the calicles. 

 It is as if an exuberant growth had forced it to cover these areas partially or completely 

 and thus to extinguish or alter the life-organs there existing. Instances of this phenomenon 

 are delineated in figs. 20, partial destruction, and in fig. 21, complete destruction of two 

 calicles, in one of which the columella is still visible. 



Propagatiov. 1. Through ova. That this has taken place is evident through the 

 many small incipient polyparies consisting of a few polypierites, which have sprung out 

 from a single primär}^ one. (See figs. 25 — 27). This must of necessity have originated 

 out of an ovum, passed through a larva stage and then fixed itself, secreting an epithecal 

 envelope around itself. It has the form of a cornet, rapidly increasing in breadth, the 

 theca is blackish, glossy and transversally finely striated. In a section, about one 

 millim. above the initial tip (f. 30) only three small septa have been developed, and these 

 are situated on that side of the polypary on which this lies fixed to the shells (fig. 26 — 27). 

 And there is in the beginning no sign of any coenenchyma. This develops on the 

 bottom side, the upper side left without any (fig. 25 — 27) and out of this new calicular 



K. Sv. Vet. Äknd. Haodl. Band 32. -N-.o 1. ö 



