140 



200 ja in width. The stock is branched and on the vertex there are 

 minute knobs. The anchor-plates (Fig. 10. 4) measure ca. 230 fju 

 in length by 160 ^ in width. They are very regularly shaped, 

 and differ from the plates in the other species of Euapta in being 

 nearly egg-shaped. The miliary granules are rosettes which are 

 found all over the skin and in the tentacles. In the tentacles and 

 in the oral disk there are rods. The rods in the tentacles (Fig. 

 8. 6) measure from 100 /a to 280 fi in length, and many of them 

 are more or less branched. Their surface is distinctly rough. In 

 the oral disk there are two different forms of rods. One of them 

 (Fig. 8.5), that which is found closest to the tentacles, has like 

 the tentacle-rods, a rough surface and bushy-branched ends. The 

 other sort (Fig. 8. 7), that which is found closest to the mouth, is 

 quite smooth and does not measure more than 100 to 150 (jl in length. 



Euapta magna is the most nearly related to godeffroyi, but 

 differs distinctly from it in having no web between the digits, and 

 in the shape of the anchor-plates, the curved rods and the cal- 

 careous ring. 



Polyplectana Clark. 



Clark. 1908. The Apodous Holothurians, pag. 76. 

 — 1924. The Synaptinae, pag. 468. 



Genotype: Synapta Kefersteinii Selenka. 



This genus is closely related to Synaptula and it is not quite 

 certain that it really represents a separate generic type. The two 

 genera do not differ in more than two characters, the number of 

 the tentacles and the shape of the miliary granules. The number 

 of the tentacles is in Synaptula usually 13, but species are known 

 with 10 — 12 and 15 tentacles. All the known species of Poly- 

 plectana have normally 25 tentacles, but this number is not constant 

 as it may vary from 16 to 27. In the collection at hand the number 

 of tentacles in Polyplectana varies from 18 to 27 and in "The 

 Synaptinae" Clark mentions a specimen with 16 tentacles, and 

 furthermore writes: "The number of tentacles shows great diversity 

 and is not closely correlated with size". For this reason it is 

 quite impossible to say to which genus a specimen with 15 or 16 

 tentacles may be referred, when we must rely on the tentacle- 

 number alone as generic character. The other character is seemingly 



