Protistplnnktoii. 



which arc rounded off. A small portion nf tin' central part of the 

 shell is stronuiy convex, forming a pioliiHiiii- hail shaped cap on 

 either side (pi. X, f. 3!)c). 



SijKtcm of Ehn/n: From an inner little spherical siiell 4 radial 

 lods extend in the form of a cross tn the 1st rin^', which forms 

 an irregular ipiadrani-ie with rounded corners. The radial rods 

 pass throuijh the middle of the sides. Beyond this rinj? thci-e are, 

 on the specimen illustrated, G — 7 rings, each joined to the one next 

 outside by a continually increasing number of radial rods. It is 

 likely that the number of the lings increases as time goes on. The 

 iinier rings are still somewhat angular, the outer, however, more 

 iei;ular. The outmost ones seem, however, again to show irregu- 

 larity, which perhaps, disappears with age. 



Purf>:: The strougly convex central part, which corresponds 

 fairly well to the 1st ring, has iiuiisually large, roundish, hexagonal 

 pores, which are much broader than the separating walls. The 

 I'est of the pores are exceptionally small and uneven in size, most 

 of them being narrower than the intermediate spaces, or of the same 

 width as these, very little lai'gcr outwai'ds, -2—3 on the space bet- 

 ween two rings. 



L'adial sjiiucs: Around tlie disc (in the imperfectly developed 

 individual, cfr. the illustration) a few very narrow, needle-shaped 

 radial spines protrude, apparently in no detinite order. Numerous 

 radial rods are to be found between the outer rings; some go 

 through two or more, others again only connecting two rings. 



B/jsjiinrs: Very small, almost punctiform, short byspines, lar- 

 gest and closest together on the convex cential part, the others 

 being only scattered over the disc. 



Dimensions: Diametei' of 1st ring 30 \>., of 2nd 42, of 3rd 

 39. of 4th 78, of 5th 98, of 6th 120, of 7th 144, 8th ring irregular 

 and as yet incomplete. The rings are thus somewhat broader ont- 

 A\ards. The large pores on the central part 5 — 6 m the small ones 

 only I V2— 3— 4 |i. The few piercing radial spines only protrude as far 

 as a distance equal to the breadth of the rings. The disc is 37 [j. 

 thick at the convex central part, outside this 30 11, only about half 

 as thick at the margin. 



The specimen which is illustrated seems to me to suggest that 

 the few piercing radial spines are in reality radial rods which 

 penetrate several rings, similarly to those which are seen here and 

 there farther in between the rings. In this case, it is hardly cor- 

 icct to cousidei- them as the radial spines characteristic of the 

 Lienus Sti/lodictija. The above species might just as well, for that 

 matter, be classed as belonging to the genus Forodiscus (without 

 marLiinal spines); but as one cannot be sure whether there may not 

 be radial spines on the outside ring in the fully developed indivi- 

 dual. I have retained the species under the genus Stylodicti/a, where 

 it ^\ould at once be placed after a less critical examination. It is 

 certainly also closely related to the following species. 



In structure it is very like Forodiscus orhiculatns Hck. (L. 80, 

 p. 492, pi. 29, f. 1), which, hoAvever, wants the very charac- 

 teristic, coarsely porous, central part. This has the appearance of 

 a spherical shell with a diameter greater than the breadth of the 

 disc, with a smaller sphere in the middle (this sphere is the inner- 

 most shell) and with equatorial rings outside. 



Only twice noticed in 1899: In the sea otf (iaukværo, '7i, 

 0—700 m.; in the sea oft' Rost, --/;, — 900 m. This makes it 

 very probable that it is an oceanic, deep watci- species, which only 

 exceptionally comes to our coasts. 



S. validispina Jciito 11. «p. 

 (PI. X, f. 40). 



The structure is, on the whole, the same as in the foregoing 

 species. The strange, peculiar, strongly convex central part is, 

 however, wanting (the disc is homogeneous) and the margin is fur- 

 nished with numerous stiong sjiines which are almost i-egularly di- 

 stributed. 



Shit pi' of III,- slirll ,11 siilf ricw: Hi'oadly linear (the di.sc is of almost 

 even thickness) but little narrower at the margin than in the middle, 

 with sharp or obtuse corners, not clearly rounded otf at the ends, 

 but almost scjuai'e. There are short sitines scattered on the cen- 

 tral pait. 



Thr si/slrn, of nniis: From the innermost little shell 4 radial 

 rods extend in the shape of a cross to the fir.st ring, as in the 

 preceding species. The ring itself is also here an irregular quadrangle 

 with rounded corners. Outside this ring, there are three others, 

 connected to each other by radial rods Avliose number increases 

 outwards. In the prolongation of the 4 primaiT radial rods (from 

 the inmost shell) may be seen, more or less clearly, some similar 

 ones which arc rather crookedly placed, aud these conjoin to form 

 4, more or less definite, zigzag rods, which go through the whole 

 system of rings. On the outside ring there are numerous (21) 

 equatorial, narrowly conical, marginal .spines. 



Pores: The pores in the centre are very small, punctiform, 

 very scattered ANith wide intermediate spaces, gradually larger out- 

 wards, on the two outer rings about 2 on the space between the 

 rings, uneven in size, up to 4 \>. or a little larger. Between the 

 pores on the central part very small, punctiform byspines are .scat- 

 tered, which may easily be overlooked. 



Radial spines: Numerous, narrowly conical (subulate), strong 

 radial spines of ditterent lengths, the longest being little more than 

 V2 of the radius of the disc. Some project out from the i-ing next 

 to the outside one, several too from the one next to the inmost 

 one, and yet a few from the innermost one. 



Byspines: A few scattered ones, very short and vei-y small, 

 needle shaped, extend from the central part of the disc. 



Dimensions: The diameter of the inner shell 14 |i., of the first 

 ring 34, of the second 60, of the third «4. of the fourth l(t2. In 

 thickness 24 |).. 



The specimen illustrated appears to be almost fully developed. 

 Probably only the small portion of the outer rinn which is not 

 seen in the illustration, is all that is wanting. 



This species exhibits a certain amount of agreement with S. 

 stellata Bail. (L. 9, p. 6, pi. 1, f. 20), which has, however, fewer 

 and broader spines, and also diifers in other respects. 



Only once found: Sea off ROst, "A 1899, 0—900 m. (together 

 with the preceding and the following species). 



S. aculeata JijRc;. n. sp. 

 (PI. X, f. 41). 



This species corresponds well in structure to the foregoing 

 one, but differs in a marked degree with regard to its radial spines, 

 which are particularly numerous, and are more irregularly placed, 

 not all lying at the same level, that of the disc, but pointing ob- 

 hquely beyond and beneath it. 



Shnpe of tlie shell, in side riew: Broadly linear, with rounded 

 corners and ends. From the centre to near the margin, there are 

 small scattered punctiform byspines. 



