Protistplankton. 



'I'liorc arc two ratlK-r n'L'ular jiciitaiions. liaviiii^- one side in 

 (■umiiioii. 'riioir i)laiu'.s funn an aiiLilr of almnt 120". At the four 

 corners there ;ire long- spines, pointing obliiiueiy outwards in differ- 

 ent directions. Between tlie fifth corners, one in each pentagon, 

 opposite to their connnon side, there is a tiirec-jointed connecting 

 arch, bent outwards from both the pentagons. This arch carries in 

 tlie two corners wiiicii do not lie in the oi-iginal pentag-ons (but 

 farti\cst away from tiicni). two long, diverging spines. 



G. pritiiordialis JoK(i. a. sp. 

 (I'l. XIV. Hg-s. (34— (i8). 



1 will add a few remarks to the description already given of 

 the genus. In most positions, this species will have the appear- 

 ance of a more or less distinct pentagon, with long spines at the 

 corners, and also a connecting arch with three similar spines. 

 Looking straigiit towards one of the two pentagons (with a side 

 in common), the connecting arch with its spines, will look like two 

 long spines, connected by a short cross beam. 



I cannot say where this species really belongs, but judging 

 from the skeleton and the position of the central capsule, it would 

 seem to belong to the Katssellaria. I have, however, only once 

 seen the plasmatic parts. The species does not seem to be so very 

 rare, but is easily ovei'looked on account of its small size. 



Found in i-ather many samples from deep water, always in 

 small numbei-s. 



Distrlhuf'iou : Also on the west coast of Noi'way. Probably 

 boreal oceanic. 



Protosceninni n. gen. 

 PI. XV, fig-. 69. 



With regard to tiiis interesting form, reference should be made 

 to the introduction to the group Nasucllaria. In the following, it 

 is placed as Cladoseeiiium and the species belonging to the Cyrtoidea 

 gioup, with the spine D upwards and the spine A downwards. 

 The expression, ,.tiie apical spine" therefore here has the same 

 meaning as with Haeckel, but is the same as the spine D in the 

 foregoing. 



Further, in the following L^. denotes ,,the left'', Lj „the right" 



lateral spine, cfr. above. 



The usual four, primary spines ai'e present, all about equally 

 developed, the apical one (D), however, perhaps best. The basal 

 spines form a very flat pyramid; they are most distinctly directed 

 downwards at the free ends. 



The primary verticil with three brandies on each main spine 

 is well developed, on each of the three basal ones, however, the 

 downwards pointing (outwards pointing) bi-anch is wanting, while 

 the two others everywhere point regularly upwards and outwards. 

 On the apical spine (D) all three branches are well developed and 

 lie about parallel to the basal spines. All the main spines have 

 also a protruding middle stem, which is about equal in length to the 

 primary branches. 



Between sets of two of those primary branches which are 

 nearest and belonging to different main spines, a strong, connecting 

 arch is developed near their ends. Of such arches, there are alto- 

 gether 9, 3 basal and 6 apical ones. 



Of the three basal ones, one runs in a ventral direction, be- 

 tween the ventral branches of the lateral spines, the two others 

 laterally, between the dorsal branches of the lateral spines and the 



corresponding branches of the dorsal spine (A). From the dorsal 

 branch of the apical spine two apical arches extend to tlie right 

 and left branch of the dorsal spine, and in the same way, two 

 apical arches from the apical spine's (D) right lateral branch to the 

 two branches of the right, lateral spine, and two apical arches 

 from the left, lateral branch oi the apical spine to the two branches 

 of the left, lateral spine. 



These arches all meet in twos the branches at the same point, 

 at a short distance from tlicii- end. There may also be found a 

 weaker, secondary arch branch extending from the same points of 

 the primary branches, but connecting together in twos the bran- 

 ches of the same main spine, or connecting these branches with 

 the protruding middle stem. In this way, a network which is, 

 on the whole, very open, is formed of very large meshes and thin 

 beams with 9 short spikes protruding from a regular verticil of 

 three branches (the G spikes being basal, the 3 apical) and 4 

 longer simple spikes (3 basal, 1 apical). 



This is an interesting species which, as proved in the intro- 

 ductory remarks, may be considered to be the original type for 

 the genera Euscmium Hck. aud Clndoscciiiiim Hck., with a nearly 

 central columella. 



P. simplex (Cl.) 

 (PI. XV, fig. 69). 



Plectaiiiuiii simplex Cl. L. 30, pi. 3, fig. 3. 



Cfr. the description of the genus and the introductory remarks. 



Each of the primary branches of the main spines has, as al- 

 ready mentioned, near their end, a verticil of 3 branches, of which 

 the two are the connecting arches mentioned above, the third bemg 

 a short spine about equal in length to the free end of the branch. 

 This spine may — as above mentioned — be connected %nth one 

 of the approximate corresponding ones, or with the protruding part 

 of the main spine, by exceedingly fine arches. 



Here and there on the outer arches fine byspines are found, 

 which ai-e perhaps partly developed into such hair-like connecting 

 arches. 



The species is no Pledcmium in Haeckels sense. Cleve 

 draws the apical spine as protruding from the common starting 

 point of the basal spines, and has, probably for this reason, classed 

 the species as belonging to Hck.'s genus Plectanium. 



I have seen only a few individuals of tliis species ; but I have, 

 nevertheless, no doubt that its characteristic structure in all important 

 points is as above described. Older individuals have, perhaps, a 

 more richly developed network of added, secondary arches. 



Rare and only singly: "A 1899, 40 miles N. \\'. of Gauk- 

 værø, 0—700 m. Is, however, easily overlooked. 



Distribution: Only noticed by Cleve from two places: 78" 

 n., 3" w., deep sea haul; 56° n., 36" w. Pi-obably also boreal 

 oceanic. 



Ensceninm corynepbortmi Joro. 

 (PI. XV, fig. 70). 



JoRG. L. 91, p. 77. 



Has the four primary spines, about equally developed, and the 

 ventral, sagittal one. 



The main spines are broad, three-edged, broadest in the outer 

 half. On each edge there are from 3 to 5, oi' more, strong, slen- 



