THE SYSTEM OF PHYLLOPHORIN/E. 



73 



Pedicels. — Pedicels seem to be but little retractile and measure 

 2.5 — 3 mm. in length. They form a zigzag row in each ambulacrum, 

 though in contracted specimens they are often seen in a double or 

 quadruple row. Near ends of body they are arranged in a single 

 row in each ambulacrum. Interambulacra are naked. 



Calcareous deposits. — Tables are always found in the introvert 

 (textfig. 3, b — f). The disk is usually oval with entire or sometimes 

 wavy margin (c — d) ; its longer diameter 0.045 — °-°7 mm., and the 

 shorter 0.03 — 0.06 mm. Holes 4 — 16 in number, usually regularly 

 distributed ; of the four larger holes, which are separated from one 

 another by the primary cross, one pair is larger than the other. 

 Spire 0.025 — 0.03 mm. high, consisting of two pillars united at top to 

 form a crown armed with 4 — 8 teeth (f). Only in the specimen 

 from Sagami Sea, which appears to be the youngest of all I have 

 had, some calcareous deposits are found very sparsely in the general 

 perisome. These are imperfect in form, being fragmentary or partly 

 dissolved ; the more perfect forms I have found are shown in text- 

 figure 3, g-i. The deposits may be said to be of the form of a 

 table with two rudimentary pillars and with four central and some 

 peripheral holes. The largest measured was 0.105 mm ' long and 

 0.055 mm. broad. Around the anus there exist five anal teeth ( o ), 

 each irregularly triangular in form and lying with the obtuse tip 

 directed posteriorly. They attain 0.35 mm. in length and 0.22 mm. 

 in breadth. Besides them, there are found in their proximity some 

 scattered X-shaped rods similar to those of tentacles, together with 

 imperfectly shaped end-plates. In pedicels a single end-plate and 

 a small number of supporting buttons are found. The end-plate (m) 

 is well developed, its diameter varying within range of 0.25 — 0.4 mm. 

 The supporting buttons or curved plates (n) are found only in the 

 vicinity of the end-plate. They are up to 0.14 mm. long and about 

 0.05 mm. broad, and are curved in adaptation to the curvature 

 of the wall of pedicel ; they are pierced by holes in two or 



