KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND. 19. N:0 7. 55 



by Otto Frederic Muller, and described by his editor Abildgaard ^), as terminating 

 in a stellate disk, the rays, fifteen in number, being clavate and alternately longer. 

 They are robust, straight, obtuse at the top, slightly contracted at the base, and 

 strengthened by an inner calcareous rod of peculiar conformation, conical, not rising 

 from the centre of its basal circlet, but almost directly from its very margin, and 

 made up of numerous longitudinal, linear and straight fibres, with short transverse con- 

 necting processes, but becoming compact near the point, jig. 129. The central part of 

 the disk is a cup, fig. 127, the margin of which sometimes is waved irregularly, some- 

 times formed into lobes closing over it. In Echinocardium cordatum, PL XI, fig. 120 

 — 126, it likewise bears a cuplike projection, the lips of which present various forms, 

 depending on their different degree of contraction, but it is sun^ounded by a marginal, 

 single row of numerous, even up to forty, unequal, slender and clavate filaments, each 

 containing a straight or very slightly arcuated, needle-shaped rod, fig. 121, composed 

 of a small number of calcareous fibres rising from the margin of the basal circlet of 

 network, but soon contracting, becoming nodular, swelling again, and spiny near the 

 top. Neither of these two species of Echinocardium presents any trace of a central 

 network at the bottom of the cuplike projection. In Breynia Australasia; Leach, PL 

 XI, fig. 131, the long and slender frontal pedicels, within the peripetalous and internal 

 fasciola, are provided at their truncated, not disciferous ends, with a few marginal, very 

 short, conical processes, evidently answering to the filaments of others, each supported 

 by a strong and solid calcareous rod, with traces of reticular texture only at its base, 

 and somewhat resembling the rods in Echinocardium flavescens. 



The shafts of the pedicels are prolongations of the external tegument, each 

 rising over a geminous pore. With the exception of the branchial pedicels, they ai-e 

 cylindrical tubes, flexible and extensible in an eminent degree. In Brissopsis lyrifera, 

 PL IX, fig. 90, I found the wall to be made up of: an external layer, a; a thick layer, 

 h, consisting of connective tissue and nervous elements, with imbedded pigment cells, 

 red and yellow; a thin, homogeneous, transparent layer, c, in which the calcareous 

 spicules are deposited; another, d, of delicate, transverse, muscular fibres, and, Avithin 

 that, a much stronger one, e, of longitudinal muscles; and, innermost, /, a rich plexus 

 of multipolar nucleated cells, the true extension of which I could not make out at the 

 time, and which seemed to occupy, to a great extent, the lumen of the tube. This struc- 

 ture was observed in the tubular shafts of the pedicels of the front ambulacrum, and 

 it appeared to hold good in the others also. 



The transverse spicules of the homogeneous layer c are disposed into longitudinal 

 rows. Generally they are the most minute of all the various calcified deposits, some- 

 times numerous, and then densely packed in the contracted state of the pedicel, in 

 other instances rather scarce, even apparently wanting in tlie phyllodean pedicels, 

 rarely so in the subanal, frontal or ventral. They are more or less arched, sometimes 

 bent, as in Echinocardium cordatum. III, PL XI, fig. 120; slender, slightly fusiform, 

 nearly smooth, as in Metalia, III, PL X, 105; Maretia, III, 104; Palajotropus, subanal, 

 ') See above p. 43. 



