PENNATULIDA. 



57 



The most complete specimen is Nr. u from the Skager Rak, in which the whole peduncle is 

 preserved; the upper end, however, is broken off 3). The four specimens Nr. 3, 7, 8, and 10 are of especial 

 interest because their upper end is intact ; this shows that any supposition that the genus Protoptilum was 

 constructed like the Virgularise, is unwarranted; when the top is so often wanting, and the calcareous 

 axis appears naked for a greater or less distance, this in Protoptilum is with tolerable certainty only 

 due to mutilation, generally caused by the fishing apparatus. In the four mentioned specimens the 

 rhachis terminates above as a longer or shorter process (fig. 4 t\ bent towards the ventral side in a 

 more or less hook-like way; this process is covered with zooids to the point; the point itself may be 

 occupied by a zooid, which, however, does not appear to be larger or upon the whole built differently 

 from the others. 



No stress can be put on the differences with regard to the size of the spicules; in the first 

 place, I have by no means always measured exactly the largest and the smallest specimens, and 

 secondly, the measurements of the specimens of the North-Atlantic Expedition and of the type- 

 specimen of the species P. thomsoni, have been made by Danielssen and by Kolliker, and these 

 measurements I have not been able to control; besides, spicules are upon the whole often very 

 varying both in length and thickness in different individuals of the same species of Pennatulids. 



As to the colour of polyps and zooids, and consequently of the rhachis as a whole, it is also 



r ) Is said to be as in the other species. 



2 ) The oblique series are here most easily seen to be such, when viewed in a direction opposite to that in the other 

 specimens, viz. from the dorsal polyp upwards towards the ventral median line. 



3) This specimen was in the Riksmuseum in Stockholm labelled as tPr. gunhilda>T>, but the name has never been 

 published (comp. Grieg. Ovs. Norges Penn. p. 21). 



The Ingolf-Expedition. V. i. 



