119 



in width, and the width-index is ca. 71. The stock is finely 

 toothed and the arms are smooth. On the vertex there are minute 

 knobs. The anchor-plates (Fig. 3. 6 — 8) are oval and measure ca. 

 700 ii in length by 425 ft in width. The central hole is large and 

 without a network as that found in the plates of maculata. Around 

 the central hole there are usually seven large holes and in both 

 ends of the plates some additional smaller ones. This shape is the 

 characteristic one, but in one of the specimens there are some 

 plates with somewhat wider ends (Fig. 3. 8) and with a correspond- 

 ing larger number of the small additional holes. Many of the anchor- 

 plates are not fully developed and then without a bridge and with 

 an incomplete margin. Rods are wanting in the oral disk and in 

 the tentacles, and the miliary granules (Fig. 2. 11) are ca. 15 — 20 fi 

 large rosettes. 



This species differs distinctly from the forms described above, 

 in its peculiar colour and in having a distinct web between the 

 digits. Besides, also the anchor-size and the shape of the anchor- 

 plates afford good characters. The aberrant specimen from Tahiti 

 described by Clark in "The Synaptinae" may be regarded as a 

 specimen of oceanica. For the present we do not know other local- 

 ities for this species than Tahiti, but it will probably be found also 

 in other places of the Indo-Pacific Ocean. 



Opheodesoma Fisher. 



Fisher. 1907. The Hawaiian Holothurians. pag. 723. 

 Clark. 1908. The Apodous Holothurians. pag. 73. 



Genotype: Opheodesoma spectabilis Fisher. 



Remarks: The genus Opheodesoma is in the collection at hand 

 represented by 29 well preserved specimens, which may be divided 

 into eight different groups. The characters used for the separation 

 of the groups are not well defined and for this reason it is for the 

 present not possible to say definitely whether the mentioned groups 

 really represent different species; but as they are easily separated, 

 I suppose it the better course for the present to regard them as 

 independent species. 



The characters which are most usable for the systematic of the 

 genus are: the presence or absence of a web between the digits, 

 the shape of the calcareous ring and the shape of the anchor-plates. 



