12 



PENNATULIDA. 



served, agrees completely, on the other hand, with Penn. aciileata as to outer appearance, has the same 

 long, narrow wings etc.; but in this specimen also the red colour passes into the violet, even if the 

 red is more conspicuous. 



By closer comparison with our Museum's type-specimens of Pcnn. aaikata Kor. & Dan. from 

 Christianssund , complete correspondance is found in such features as the number of polyps in the 

 wings, the double row of lateral zooids at the base of each wing, the 4—6 rows of dorsal aculei; but 

 in the length of these latter there is a conspicuous difference. Whilst the spines of the Norwegian 

 specimens are 1—2""" long (according to Koren and Danielssen they may grow to a length of 3-3""": 

 Fauna litt. Norveg. 3, p. 87), in the two Greenland specimens they are fully 4™™ long. American 

 specimens in our Museum (from the Atlantic: 36° 55'— 58° N. Lat. 71° 13'— 14' W. Long., depths 207—214 

 fathoms, and 40" N. Lat. 70° W. Long., 260 fathoms), both by their strong colour, which is redder, how- 

 ever, and by their long and stout spines, resemble the Greenland specimens very closely ; when to this 

 is added, that the Iceland specimens brought home by the .<Thor:, stand as to colour between the 

 two Greenland ones, and that specimens of Penn. aculcata are also enumerated from several other 

 Atlantic localities with spines of more than 3 and up to 4""" (Marshall, «Triton»-Penn. p. 124, Kolliker, 

 Monogr., Appendix p. 366), there can be no doubt that the specimens from the Davis Straits are justly 

 referred to this species. Both the colour and the size of the spines also, to judge from several state- 

 ments in the literature of Penn. actileafa.^ would seem to vary according to the depth at which it is 

 found; at great depths the ventral calyx-tooth of some of the large zooids is developed to a powerful 

 spine, and the colour becomes more intense, deeply red or violet. 



The following features refer to the two Ingolf specimens: 



Total length 



Length of peduncle 



Number of pinnulse 



Length of a well-developed pinnula 

 Number of polyps in such a pinnula 

 Length of the largest aculei (zooids) . 



Nr. 1. 



Nr. 2. 



105 mni 



50 » 



19/17 

 iqnim 



8-9 



A mm 



48 



22/22 



24 mm — 25 'nm 



7-9 



4 mm 



The .specimen Nr. i (PI. I, fig. i) is provided with spicules differing somewhat from the form 

 common to the species, being more slender, more spatulate at the end, and very strongly coloured; 

 some of the polyp-spicules, moreover, reach a very considerable length; the largest ones measured are 

 3-I20""" long and o-io8""" broad, whilst the smallest measured (from the tentacles) 0-080'"™ in length 

 and ca. o-oo8""" in breadth. The specimen Nr. 2 shows, both in the form of the spicules and their 

 length, a tolerably close agreement with the American specimens of P. aculcata examined. The longest 

 measured spicules from one of the aculei were 2-160""" long and 0-096""" broad. 



In the specimen Nr. i the top of the rhachis is .so much contracted and partly damaged, that 

 its more particular structure cannot well be made out; in Nr. 2 the rhachis is terminated above by a 

 rather large individual with three-toothed calyx; this may possibly be a somewhat uncommonly deve- 

 loped terminal zooid, possibly the transformed terminal polyp; in the latter case, the terminal zooid 

 must have disappeared. 



