1885.] DR. HUBRECHT ON A NEW PICNNATULID. 515 



exterior. This expansion, which was characterized by its more 

 brownish-yellow colour from the rest of the red polyparium, is now 

 seen to owe this different coloration to the absence of spicules in this 

 part ; the spicules are seen to diminish in size in the vicinity of the 

 disk (fig. 9), several of them being yet imbedded in its circumference, 

 but none in its central portion. The gradual passage of this 

 sclerenchvmatous tissue into the rest of the investment of the poly- 

 parium is more clearly visible in the adjacent longitudinal section. 

 It may be further gathered from the figures 10 & 11, the former 

 figure at the same time serving to demonstrate both the directions in 

 which the spiculae are placed in the wall of the stem, and the more 

 or less complicated trabecular arrangement of the sclerenchyma, as it 

 is found inside the outer spicule-bearing layer and surrounding the 

 spaces in the stem. 



I have, finally, to mention numerous pores by which the walls of 



OV»* 



Figs. 1-3. Echinopdlum inacintoshii. 1. Transverse section of lower part of 

 stem. 2. Ditto of upper part of stem. 3. Ditto of rliacbis. 



Fig. 4. Cavernularia liitkenii. transverse section of lower part of rbachis (after 

 Kolliker, I. c. pi. 23) ; a, axis. 



the polyparium are perforated, and which in transverse sections are 

 found to correspond to the small zooids. From this it follows, and 

 the sections moreover entirely corroborate the conclusions, that these 

 pores are more numerous on the dor.sal surface {cf. fig. 6) than else- 

 where. One of these pores is represented magnified and in transverse 

 section in fig. 8. Remains of polyps could in my specimen not be 

 detected in the cavities into which these pores lead ; still from 

 analogy I feel justified in calling the external small polyr--'""'^ ^^i 

 corresponding to these openings, zooids. After having thi. s giv po^J?" 

 attention to the external and internal characters of the polyp^rmm, 

 we should have to examine the soft tissues, the polyps themselves, 

 the reproductive apparatus, &c. Unfortunately the one specimen I 

 felt justified in dissecting has hardly anything to teach us in that 

 respect. The remnants of the polyps extruding from their polyp- 

 cells were well visible even with a hand-glass, upon superficial 

 examination of the specimen, and even a number of long tentacles 

 could be seen to belong to each of the polyps. They had, 

 however, so flat and shi'ivelled an appearance that I was doubtful 

 whether they would give any histological information when section- 

 ized. My doubts were realized, and I have come to the conclusion 

 that since 1874, when the polyparia were captured, they must have 

 gone through a phase of desiccation, although when I received them 



