E. Jørgensen. 



Ring- and 

 view (f 



Dkfi/ocircns : 

 leshes f, apiea 

 leniatically). 



On the dorsal side of the ring-, there is a long spine, pointing 

 obliquely backwards and upwards, the apical spine. A, in the plane 

 of the ring-. On both sides of this apical spine, there are two 

 lai-ge, pentagonal meshes, diverging at right angle on each side, 

 both in the same plane perpendicular to the plane of the ring. 

 These are the right and left transverse meshes, a^, and aj. These 

 meshes are again both in a dorsal and ventral direction joined to 

 two similar pairs of meshes, the dorsal lateral meshes, f and fj, 

 situated in a dorsal direction from the transverse meshes, and the 

 ventral, lateral meshes, bj. and bj. These lateral meshes point ob- 



li(iuely outwards from the plane of the ring. They are thus not 

 in paii'S in tiie same plane, but the plane of the right one forms 

 an angle with that of the left one, both being turned from a po- 

 sition perpendicular to the plane of the I'ing in a direction away 

 from the centre (tig. IX). 



In a ventral direction from the pair of 

 meshes b, ."3 — 4 more or less complete pairs 

 of meshes follow, c to e: in a dorsal direc- 

 tion, however, there ai-e only three protruding 

 spines, g, the middle one being in the plane 

 of the ring, the other two pointing obliquely 

 outwards and downwards. Himilar protruding 

 spines are found at several points (cfr. the 

 description of the species). 



Although I am but imperfectly acquainted 

 rtith this form, havhig only seen a couple of 

 individuals, I have endeavoured to trace its 

 structure as complety as possible, as it is a very 

 interesting form, which seems to be well suited to throw light upon 

 the connection between the ring forms of Nassellaria and the group 

 F/crtoidcu HcK. on the one hand and the group Zygospyrida Hck. 

 on the other. 



The connection with the latter seems to me to be quite evident, 

 leaving scarcely no doubt that such forms as Ceratospyris are 

 evolved from a ring like Dictyocircvs with a further development 

 of meshes on both sides outside those described, until there is on 

 either side formed a closed network. The conspicuous narrowing in 

 Ccrdtospyrts at the sagittal ring corresponds very beautifully to the 

 right and left meshes which extend forwards from the ring, e. g. 

 in the pair of meshes b and f. 



The connection with the group Flectoidea is less clear. On 

 this point, however, the genus Campylacantha seems to furnish 

 valuable information. As above mentioned, I consider the sagittal 

 ring to be formed by the connection of the dorsal and ventral sagittal 

 spines (or of meeting branches). Further, I consider the branches 

 lij,, li| between the meshes a and b to correspond to the ventral, 



lateral spines in Campylacantha, and the branches i , ij between 



the meshes a and f to correspond to the dorsal, lateral ones. In 

 this way too, the large transverse meshes a, diverging at right 

 angles, situated between the dorsal and ventral lateial spines in 

 Campjylacantha, are explained, as well as the centrifugally directed 

 pair of meshes b and f, formed by the partly forward pointing 

 ventral, lateral spines, and the partly backward pointing dorsal, 

 lateral ones. 



/). clathratus Jiirg. n. sii. 

 (I'l. XIII, fig. 48). 



To the description above, I will add the following, which 

 applies to the individual illustrated: 



After the pair of meshes a and b, there follows in the same 

 direction (ventrally) two strong, but smaller meshes, c, one on each 

 side. In the corner between bi and Cj there is a secondary, smaller 



mesh. After Ci there follows yet another mesh, d|, while the cor- 

 responding one on the right side is wanting, but there is a trace 

 of it in the shape of a protruding spine. (This mesh is probably 

 developed in elder individuals). Then comes a pah- of strong, 

 obliquely diverging spines, k, and then two similar ones, g, with 

 an intermediate one in the plane of the ring, which spine might be 

 considered to be the protruding point of the primary dorsal (basal, 

 sagittal) spine. Following this bundle of three spines there are. 

 in the same direction, the two large meshes f, which again stretch 

 up to the pair of meshes a. 



On the strongei' branches, there are several protruding spines, 

 which generally point obliquely outwards from the plane of the 

 sagittal ring, in a direction away fi'om the centre. Besides these, 

 there are three spines protruding in the plane of the ring, the 

 apical spine, the protruding, dorsal, basal, sagittal one at g, and 

 the protruding, ventral, sagittal one between the meshes b and c 

 (broken off on the specimen illustrated). 



In addition to these, we have some secondai'y spines, as for 

 instance the conspicuous twins on the outer side of a|. The two 



meshes b^. and bj are connected by an arched (ventral) beam which 

 is bent outwards, and carries in the middle a I'ather strong, se- 

 condary spine pointing outwards. 



The sagittal ring and all the stronger bi'anches and spines ai-e 

 three edged. 



The diameter of the ring is about 50 |j.. 



The individual described was probably not fully developed. 

 Judging fi'om the many surprises which have met me with regard 

 to imperfectly developed radiolaria, I cannot but remark that it 

 is perhaps not altogether impossible that the Dktyocircus clathratus, 

 here described, is a young form of Ceratospyris or a similar spe- 

 cies of the group Zygospyrida. 



This species does not answer well to Haeckel's system, so 1 

 have been obliged to classify it as a separate genus. It would have 

 had to be classed as belonging to the group Semantida Hck. in 

 which there are species which in structure in important respects 

 undoubtedly agree very well with the species here described. It 

 especially answers well to the genera Semantid'nim Hck. and 

 Semantiscm Hck., both of these having the three large pairs of 

 meshes corresponding to a, b and f. These genera have, however, 

 not the long apical spine. 



Very rare and only singly: Henningsvær, '-'"/s 1899, — 

 28(1 m. 



VII C. li. Zyje^ospyrida Hck. 

 C«'rato><|>} riN Hik. 



1 do not consider this genus to be well characterized by H.veckel; 

 but it is, at any rate, easily I'ccognized. 



In the material examined, I have only found one species be- 

 longing to it. 



C. hyperborea Jorg. n. sp. 

 (PI. xm, fig. 49). 



I have only seen very few individuals of this species. Its 

 structure seems to be of precisely the same type as that of Dictyo- 



