138 



E. Jørgeus 



the neck, hence running for a little way in the thoracic wall, 

 and then protruding either as ('thoracic „feet" (D. histncosus), or 

 leaving the thorax above its free brim. 



The thorax is broadly campanulate oi' conical. 



D. Clevei Johg. 



D. yracilipcs Ci-. L. 3(i. p. 21). pi. 2. f. 2. vix Bail. D. 

 ■Chvei Johg. L. 91, p. 80, pi. 5, f. 26. 



The protruding part of all live spines of uniform breadth, much 

 broader than the inside part, with three distinct edges. In 

 young specimens, the three basal spines extend from the lowei' part 

 of the thorax. They are partly running in the thorax, but on 

 older individuals always appear to protrude above the free brim. 



The irregular, small spines on the free brim of the thorax 

 arc here, as in the preceding species, only temporary formations, 

 which later on become intermediate walls between new meshes. 



In the passage from the cephalis to the thorax, there are three 

 distinct swellings, two lateral, outside the primary, lateral arches 

 (P> and Bj), as well as a ventral one between the primary, lateral 



.spines. 



The thoi-a\ is wide, flatly campanulate. 



Dictyoplihmig (jraeUijws Bail. (L. 9. p. 4. pi. 1, f. 8) does 

 not appear from the description to be this species („triquetrous; 

 three acute lidges prolonged into long acute basal spines"). 



Rare, in deep water samples. 



Distrihiitiun : Rare on the west coast of Norway. Cleve men- 

 tions D. graciliijeti from a few places in the northern part of the 

 Atlantic up to the north west point of Spitzbergen, at the most 

 noithern places only in deep water. Bailey's species was found in 

 tlie Northern Pacific and Kamtschatka. 



Probably boreal oceanic. 



D. liistricosus JiiRg. n. sp. 

 (PI. XVI, fig. 89). 



Cephalic semispiierical, thorax pyramidal. 



The basal spines extend from the central rod (under the neck 

 stricture) to the thorax and continue in the thoracic wall to the 

 very mai'gin below where they protrude as „basal feet". The api- 

 cal spine, D, runs chiefly in the wall of the cephalis (as in the 

 two preceding species) and above is prolongated to a tophorn, which 

 is only very little different to the byspines in appearance. This is 

 also the case with the ventral, sagittal spine, which runs obhquely 

 upwaids and out through the neck stricture. 



.Ml the main spines are narrow, not three-edged. 



Cephalis and thoi'ax rather plentifully provided with narrow, 

 needle-shaped byspines, which are longest and most numei'ous on 

 the cephalis. The longest are as long, oi- even a little longci', than 

 the diameter of the cephalis. 



The pores ai'e uneven in shai)o and size, varying from quite 

 small to 9 p., not much smaller on the cephalis than on the thorax. 



Here too the three .swellings on the upper part of the thorax 

 between the main spines (fig. 89 b) are to be found. 



The width of the lattice shell is 85 \)., its height (not includ- 

 ing the basal feet) 68 |i.. The cephalis alone is 34 \>. wide and 

 22 11. high. 



Very rare and only singly: '"/i 1899, 40 miles NW of (iauk- 

 værø, 0—700 m.; Henningsvær, ^'/s 1899. 0—250 ni. 



Distribution: Probably boreal oceanic. 



liitharaehninni Hck. 



Rudimentary cephalis, In the neck stricture, which here is near 

 the top of the lattice shell, the three primary meshes will be seen 

 between the three primary, basal spines. These spines are here very 

 much retrogi'aded and have only the appearance of walls between 

 the primary meshes. Both the apical spine, D, and the ventral, 

 sagittal one are wanting. Refei' for further details to Hck. L. 84, 

 p. 1163. 



^'oung forms of Litharachiiiimi tentoriunt will appear as slen- 

 dei' pyramids and thus correspond to the genus Plcctoinjramis Hck. 



Haeckel mentions and illustrates the three primary meshes 

 mentioned (his cortinar septum) but no cephalis. He too considers, 

 however, the jointless lattice shell to be the thorax, as he deflnitely 

 derives the genus from Dicijrtida by the loss of the cephalis. 



My opinion therefore is that it would be most natural to i-efer 

 all the genera belonging here to Dicyrtida, not to Monocyrtidd. 

 In this species (and probably in most eases) a rudimentary cephalis 

 is also distinctly visible. 



The genera which belong here according to Haeckel ought 

 undoubtedly to be subjected to revision. 



L. teiitorinui Hck. 

 (PI. XVL figs. 90—91). 



Haeckel L. 84. p. 281. pi. 4. flg.s. 7—10. L. 86. p. 1163. 



The upper part of the lattice shell is slenderly conical, widened 

 out below to a broad brim which is at the ouLside edge bent again 

 upwards, giving the appearance of the brim of a hat. At the top 

 of the conical part, there is a tiny semispherical cephalis. 



The pores in the upper part of the shell are small, round and 

 scattered; farther down they are lattice windows (as in the genus 

 Pledopyramis Hck.) and are moi'e I'egularly arranged in horizontal 

 rows. The shape gradually lengthens out horizontally, so that from 

 being round they become rectangular with rounded corners. Only 

 still farther down do the sti-aight ribs in the wall of the lattice 

 shell appear, and the pores now become regularly rectangular, and 

 are arranged in distinct i-ows, both radially and tangentially. ^\'lu■n 

 the radial pores have attained a certain size, new straight longitu- 

 dinal ribs appear in the wall of the lattice shell, pushed in between 

 the old ones. 



The number of jirinciiia! ril)s in the well developed specimen 

 which is illustrated in fig. 90. was 32. Very numerous secondary 

 ribs, their number increasing in proportion to the distance from tiio 

 cephalis, were present between these 32. The diameter of the 

 brim 340 'x, of the cephalis only 8—9 |j.. The largest meshes (high 

 up) 9 |x, in the brim about 6 \i.. 



Notwithstanding that there are really great diflerences in 

 Haeckel's and my desci'iptions, it seems — on account of the 

 remarkable eoi'respondence in so many details with Haeckels 

 illusti-ation — that my species and Haeckel's are after all iden- 

 tical. 



This species answers perhaps best in structure to the many- 

 jointed genera (division Stichocyrtida), and might be considered as 

 such a many-jointed form, where the strictures and annular septa 

 between the different joints have disappeared. 



Very rare, only singly: Skroven. *U 1899, 0—150 m. ; thc 

 Folden Fiord, "A 1900, 300—200 m. 



Dixtributiu'}i: In the sea between Norway and the Facroe 



