ECHINOIDEA. I. 



'57 



complicate (PI. XVI. Fig. 16), and the inmost ones show a radiate arrangement There are no spines 

 on the buccal plates; a few pedicellariaj may be found on the buccal membrane, especially opposite 

 to the gills. 



The pedicellariae. The globiferous pedicellariae (PL XVIII. Figs.6, 24) have one lateral tooth 

 on either side, sometimes two teeth on one side, one tooth on the other; the blade is almost tubular, 

 the edges being coalesced to such a degree, that only a series of small holes are left in the median 

 line, and one larger hole just below the large end-tooth. The basal part is very varying in form, 

 with more or less projecting outer corners or with quite rounded edge. The apophysis is narrow and 

 often rather irregular in the edge with a larger, oblong or rhombic hole at the upper end. The size 

 differs verv much ; especially in var. Flemingii quite small pedicellariae ma} - be found. In var. nor- 

 vrgicus numerous spicules are generally found in the stalk and head of the globiferous pedicellariae 

 (also in the neck of the other pedicellariae). The tridentate pedicellariae (PL XVIII. Figs. 1, 5, 7). The 

 valves long, narrow, and deep; the upper end of the apophysis spreads somewhat, and forms a little 

 mesh-work in the lower end of the blade; a few narrow cross-beams cross the inside of the blade for 

 a shorter or longer way. The edge is straight, thick, and set with numerous small teeth, placed in 

 transverse series (PI. XXI. Fig. 25); in the short part at the point where the valves join, the edge is 

 more or less coarsely serrate. They may be very long, up to 2'5 mm (the length of the head). The 

 ophicephalous pedicellariae (PI. XIX. Fig. 36) as well as the triphyllous ones without any characteristic 

 peculiarities. — The sphaeridiae (PI. XIX. Fig. 32) rather much grooved at the point. - The spicules 

 (PI. XVIII. Fig. 14) of the common form, numerous, especially in the abactinal tube feet; they are also 

 found in rather great numbers in the skin round the base of the spines, and even some way out on 

 the spines, in the gills, and in the buccal membrane : in the gills together with the common irregular 

 fenestrated plates. Also in the pedicellariae they may be found, especially in var. norvegicus. Some- 

 times a few S-shaped spicules may be found among the common bihamate ones. 



Synonymous with this species are Echinus rarispinus G. O. Sars, depressus G. O. Sars, and 

 microstoma Wyv. Thomson. The two former have already in Rev. of Ech. by A g a s s i z correctly 

 been referred to Ecli. norvegicus. Of Ech. rarispinus Daniels sen (no. p. 4) says that if it be no 

 distinct species it is at all events a well-marked variety that seems to work its way up to an inde- 

 pendent species . By the kindness of Prof. Collett I have from the museum of Christiania got some 

 tvpical specimens of Ech. rarispinus for examination; I can see no other thing but that they are large 

 specimens of var. norvegicus. PI. II. Fig. 2 may so far be taken as an EcJi. rarispinus , but there is 

 no reason to keep up this form as a special variety. Neither can I feel quite persuaded that the 

 small specimens with the characteristic red spots (PI. II. Fig. 6) may be said to be representatives of 

 a dwarfish variety degenerated by its confined life in the fjords (Danielssen loc. cit), as it is a fact 

 that it is not confined to the fjords, but is also found in the midst of the Cattegat and Skager Rack; 

 also from the Mediterranean and from the Bay of Biscay I have seen quite typical specimens. They 

 are scarcelv anything else than young specimens of Ech. acutzts. It is, however, to be observed that 

 such small specimens of a diameter of ca. 1 j 2 " may be sexually ripe, as pointed out by G. O. Sars 1 ), 

 and as I have also substantiated on specimens from the Cattegat. We have no proof that these small, 



M Forhandl. i Vidensk. Selsk. Christiania. 1872. p. 106. 





