292 



Chiridota aponocvita Clark. 



Chiridota aponocrita Clark. 1920. Tropical Pacific Holothurians. pag. 



125, PI. -4 fig. 1—2. 

 Taboga, Panama. 7. XI. 1915. The shore, under stones. 1 specimen. 

 20. I. 1916. „ „ 1 



„ „ 4. III. 1916. Sandy shore. 2 specimens. 



There can be no doubt that these four specimens are Clark's 

 aponocrita. Both the locality and the dense layer of "dough-nut- 

 shaped" particles leave no room for doubt. Only the one specimen 

 is complete, but it gives thus an opportunity for a closer description 

 of the species which, because of the fragmentary condition of Clark's 

 specimens, has not been satisfactorily described. 



The complete specimen at hand measures 8,5 cm in length by 

 0,7 cm in diameter. The colour is in alcohol yellowish-white and 

 semitransparent. The wheel-papillae are nearly equally spread all 

 over the body, though densest on the dorsal side of the anterior 

 end. There are twelve tentacles, each with seven pairs of digits. 

 The calcareous ring (Fig. 58. 8) consists of 12 pieces, of which 

 the radiais are perforated for the nerves. The calcareous ring ac- 

 cording to Clark has "no conspicious projections on either margin", 

 but as seen from the figure all the pieces in the specimen described 

 (as well as the others) have a distinct projection on the anterior 

 margin. A cartilaginous ring is wanting. There are .12 polian 

 vesicles, six of which are much larger than the others. The stone- 

 canal is single and the calcification of the madreporite (Fig. 58. 5) 

 is irregularly ring-shaped. The oesophagus is rather long and thin 

 and different from the intestine which has a large loop. The ciliated 

 funnels (Fig. 59. 2) measure ca. 130 in length. They are rather 

 long-stalked and not united into clusters. Where the funnels are 

 exceedingly dense, two to three may be united at the base. The 

 gonads are branched and open on a little papilla close behind the 

 dorsal tentacles. 



The wheel-diameter varies from 50 — 120 yb. Besides the wheels 

 there are found three different sorts of calcareous deposits in the 

 skin. The species is, as said, characterized by the dense layer of 

 "dough-nut-shaped" rods which, as Clark writes, are found even 

 in the skin covering the wheel-papillae. Besides these rods (Fig. 

 58. 9) there is found a second sort. These are larger and not so 



