NOTES ON APHROCALL1STES BEATRIX GRAY. 



iSl 



may be missing. Both may measure up to So/j in total length, though in 

 some stocks the length seemed not to exceed 6o/i, while in one stock it 

 reached j6/j. as regards C and well up to ioo/z as regards D. In breadth 

 both the varieties are about equal to the diameter of the larger examples 

 of regularly developed and non-elongate hexasters found in the same 

 specimen. It seems the elongate hexasters in the oriental specimens never 

 attain the same large size and the same strength in the development of 

 both shaft and rays as the corresponding spicules in some Indo-Malayan 

 specimens of the species. The figures, given by Carter ('73, pi. iii. fig. 20) 

 and F.E. Schulze ('87, pl. lxxxiv. figs. 9 & 10), of the elongate oxyhexaster 

 from the type specimen of A. beatrix Gray (from Malacca) represent that 

 spicule very much larger and more strongly developed than I have ever 

 observed in the oriental form. Also the figures given by F.E. Schulze 

 ('02, pis. xv & xvi) of the same spicule from specimens collected by the 

 " Investigator " in the Bay of Bengal, distinctly indicate the same fact. 

 That author gave for "yi. beatrix " from that region that the spicule may 

 reach 150/i in length, a size which I have never yet seen attained by the 

 identical spicule in the oriental form. — In the elongate hemidiscohexaster, 

 the terminals end either with a minute pin-head-like swelling or with a 

 small marginally toothed disc, similarly as in the regularly developed 

 discohexaster. In the oriental form I have so far not discovered a case 

 which might properly be called an elongate onychaster, such as F. E. 

 Schulze has reported from certain Indoceanic specimens of the species. 



There can scarcely be a doubt that the above two varieties of hemi- 

 hexasters (C and D) were derived respectively from the two regular 

 hexasters before noted on (A and B), but particularly from the hemihex- 

 asterous form of these, simply by marked elongation of either one or two 

 opposite principals. The prolonged principal or principals constitute the 

 straight axial shaft (up to 12/z or 24/z long), which usually bears at its each 

 end a number (3-5) of terminals in a radiating conical tuft. Rarely the tuft 

 at one end of the shaft is represented by a single terminal standing out in- 

 straight line with the shafc. The spicular center lies of course in the shaft,. 



