ACTIXOrODOUS HOLOTHUßlOIDEA. 



181 



nmnorous i)udiccls arc in three distinct zones, the middle zone 

 being, in the large specimens twice as broad, and in the small 

 specimen abont as broad, as the lateral zone. 



In one of the large specimens : Polian vesicle one, pear- 

 shaped, several cm. long, and situated on the left ventral inter- 

 radius of the circular canal. In the small specimen, Polian 

 vesicles are four in number, two being large and two small. 

 Stone-canal one, attached to the mesentery, much meandering. 

 The madreporic body in the usual position in the opening of 

 the mesentery opposite the middorsal interradialia of the 

 calcareous ring. Calcareous ring oblique, being highest and 

 stoutest in the middorsal Hue and gradually narrowing toward the 

 midventral line (textfig. 32«). Radialia four -pointed, interradialia 

 one-pointed. The notch on the posterior edge of radialia is 

 shallowest in the midventral one and gradually becomes deeper 

 m the more dorsal ones, owing to the more pronounced posterior 

 l)rolongations of these latter. 



Calcareous deposits :— ( i ) Slender tables of only one kind, 



about 0.036 mm. high, with 

 disk measuring about as 

 nmcli in diameter {b, c). 

 The latter has mostly 

 four central holes and four 

 interradial corner holes, 

 or at the most only a 

 peripheral circle uf small 

 holes. Spire with one 



titichopus varie<jatus : a — Culwirccjus iItic; ; h, c — Tublcs; i 



'Z— Rosette ; c— c-shapcd ixxiy. (h—e x 400). I— Right ^^''^iisvcrse beam, ending 



veutnaintemv.lkUa; Ira-Right clorsalinterracliditjRmv in twclvC OruiOrC tcCth 



—Mid veil tral riidiiilia ; Rul— Right doi^jil miliilii ; Rrl— 



Right liilenil nwliiUa. wllicll h'dXC a tcndcUCy 



Textfig, 32. 



