KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 25. N:o 2. 117 



Botryocrinus ramosissimus. 



(Plate V, fig. 160— Plate V[, fig. 170.) 



1878, Angelin, Iconographia, p. 24, Tab. XX, fig. 8, Tab. XXIII. fig. 14. 



1878, Botryocrinus coraUum. Ang. op. rit., p. 24, Tab. XV, figs. 9, 9 a, Tab. XXIII, figs. 15, 16, 16 a, 

 Tab. XXIV, fig. 4. 



Diagnosis. 



Dorsal cup a wide cone, with smooth IBB and BB and slightly projecting RR. 

 Articular facet occupies greater part of width of radial. IBr 2 or rarely 1 to ;i ray. 

 Arms seven or eight times length of cup, giving off long branching armlets at irregular 

 intervals alternately; arm-ossieles slightly constricted as a rule. x supports three low 

 plates of about equal size. Ventral sac bends first in an anterior direction, then curves 

 round posteriorly. Stem rather stout, round or obscurely pentagonal. 



This species is represented by a large number of specimens, many of them only 

 arni-fragments. The individuals vary mueh in size, but in other respeets their charaeters 

 are fairly constant. 



Sorne of the smaller individuals, which probably represent younger stages, were 

 separated by Angelin as a distinct species, B. corallum. It will be well to give here 

 the reasons that have induced me to merge tliis in B. ra?nosissimus. There is practically 

 no difference between the two forms except that of size. The only diagnostic charaeters 

 given by Axgelin concern the plates of the tube, which in B. ramosissimus are said to 

 be elevated and radiately ribbed towards the apex of the tube, while in B. corallum they 

 are said to be small and smooth. This difference is merely that between Aouth and age: 

 but, as a mutter of fact, the specimen of B. ramosissimus represented in tig. 8 of Tab. 

 XX shows only very slight traces of plication on the sides of the tube, while the specimen 

 named B. corallum, of which a greatly restored drawing is given in hg. 10 of Tab. XXIII, 

 shows traces no less clear on the sides of the distal part of the tube. 



The chief specimens examined are as follows: 

 it Type-specimen of B. ramosissimus, Tab. XX, fig. 8. 

 b » Tab. XXIII," hg. 14. 



c » » B. corallum, Tab. XXIII, fig. 1."). 



d » » Tab. XXIII, tig. 1 (i and Ib,/. 



'• A large specimen of which part of an arm was figured Ann. Mag. Nat. Hist., ser. (i, 



vol. VII, p. 408, i\>^. 4 [our text-fig. 17 (4)]. 

 / A large specimen with abnormal stem. 

 // A large specimen with the calyx seen in section. 

 //. A well preserved cup showing the radial facet. 



The specimens of Ii. co-rallum represented in Tab. XV, tig. !> and Tab. XXIV, fig. 4 

 are not lo be found; and this is a pity, since the former figure shows an opening a1 the 

 base of the ventral tube which is supposed to be an anal aperture. 



