286 



Th. Mortensen. 



the number of serrations cannot be stated 

 with full certainty, the only sample pre- 

 served being a little dissolved, as is also 

 the case with several of the other calcare- 

 ous plates, the specimen having probably 

 originally been preserved in formaline; 

 but it seems that there was only one ser- 

 ration on one side, two on the other. The 

 stalk is slightly widened below the arms 

 and has here an elongate hole; whether 

 this is a normal condition can, of course, 

 not be ascertained from the single sample 

 found. The basal disk of the anchor stalk 

 (Fig. 5 b) is simple, with six holes, the 

 edge being slightly concave between them; 

 in this view the stalk is seen to be com- 

 posed of three coalesced rods. The 4 — 6 

 supporting rods of the anchors are slen- 

 der, sometimes bifurcate in the outer end 

 (Fig. 5 c— d). 



The tables (Fig. 6) have mostly 3 round 

 holes. The Fig. 6 a represents the typical 

 shape of the tables; but they often are 

 more or less irregular (Fig. 6 b); the outer 

 edge may be somewhat concave, and there may be ditferent out- 

 growths, which may coalesce in different ways, so that a fourth 



Fig. 5. Anchor plates of Molpadia 

 Blakei var. grönlandica. a. Anchor; 

 h. basal plate of the stalk, showing 

 in the middle the stalk seen from 

 above ; с supporting plate, abnorm- 

 ally divided in the end ; d. normal 

 end of a supporting plate, ""/i. 



Fig. 7. Calcareous plates 

 from the caudal appen- 

 dage, ""/i. 



Fig. 6. Calcareous plates (tables) of the skin. a. the nor- 

 malform; b. slightly irregular; c, d. side view of plates, 

 showing the spire; e—g. developmental stages, ""/i. 



