HA WAJIAN ITOLOTIIVRIAX^—FTSHER. 729 



0.27 iimi. in length. There are two hirg-e central holes, but the others 

 rary so much in siz(^ that it is futile to attempt a detailed description. 

 The figures will serve to illustrate the usual type. Occasionally there 

 is an incipient handle (Plate LXXXII, fig. 4), such as is well developed 

 in Lihidoplax, but ])lat('s in the same individual vary greatly in tliis 

 respect. In specimens from a more considerable depth (Jrltll, 4142) 

 the outline of the plates is rather more even, the two central holes are 

 relatively smaller than those from lesser depths, the calcarcMms frame- 

 work is somewhat stouter, and the plates average a little larger. The 

 anchors are 0.24 to 0.85 mm. long. Many arc represented bv simple 

 rods, being in a state of development. The miliary grains varv con- 

 siderabl}' in number, being scarce in some specimens and abundant in 

 others. When present in normal numbers they are arrang(>d in two 

 series along each radius, with others scattered sparsely on eith(M- side 

 of the series. The O- and C-shaped grains are conmionest, but other 

 forms are numerous. In some specimens variations of straight or 

 slightly curved rods predominate. In the shaft of the tentacle, ('- and 

 0-shaped ))odies predominate, l)ut in the digits slightly curved rods. 

 Grains in the body range from al)out 0.04 to o.0('>5 nun. in length; 

 those in the tentacles are smaller, and those in oral disk small(\st. The 

 figures are diawn to scale. 



Although this species is undoubtedl_y closely related to Profanl'i/ra 

 chaUengti'i (Theel), there are a number of difierences of considerable 

 importance, namelv, the presence of two series of little "sensory 

 cups" on tentacles, the variable luunber of tentacles, arrangement of 

 miliary granules, as well as their somewhat ditferent form, more elab- 

 orate anchor plates. Even the calcareous ring presents points of dif- 

 ference.^' Sluiter'^ has named a variety silxxjiV of /*. cliallengerl. the 

 plates of which are more like those of the present species than are 

 typical ('Ji(illeri(/er!. In other points .^ihogiv seems to be very close to 

 cJialJengci'i^ which was taken in 140 fathoms at Fiji Islands. 



It may e\'entualh^ be found that rJuillcnget't is a very wide ranging- 

 and variable species, including possibly apparently separate forms, 

 but it is pure assumption to so regard it at present. It seems far bet- 

 ter, in view of the difierences pointed out above, to regard the Hawaiian 

 specimens as belonging to a separate species, which may well l)ear the 

 name of the fisheries steamer Albatross-. 



"Compare Plate LXXXII, %. 4«, with Plate I, fijj. 4(1, Challentrer ITohitlinrioidea. 



'^Siboga Holothurioidea, p. 131. 



'^This is an unfortunate name, since it invalidates the s/Awyr/r given on the fuliowing 

 page (132) to a different species of Protanki/ra. Since I', mbogif is now without a 

 name, it may be called Protaakyra duiterl, after its discoverer. 



