91 



of the sarcodo-spiculos of AphrocalUstes is almost identical with the ' furcate 

 spiculated biternato ' spicule from Farrea occa (Brit. Spong. Vol. I, fig. 190), 

 but more spiny. I am afraid to name this form ; but I am sure it would be 

 highly suggestive to Dr. Bowerbank." 



The following year, 1869, he described it in his paper " On Iloltenia " * 

 as " a regular six-rayed star with the principal axis longer than the transverse 

 rays and one half of it feathered." 



In 1870 1 Percival Wright described a new species of AphrocalUstes as A. 

 hocagei and in diagnosing it he laid considerable stress on the absence of the 

 " porrectomultiradiate spicules " of A. heatrix. Saville Kent J on the other 

 hand, who studied AphrocalUstes bocagci in the same year, said concerning it : " the 

 spicula of the sarcode are very different, the porrecto-multiradiate spicules are 

 not wanting, as Prof. Wright imagined, and in fact appear to constitute the type- 

 form of the genus ; but there are none of the verticillately spined ones so 

 abundant in A. Beatrix." 



I myself examined and described § a specimen, labelled AphrocalUstes beat- 

 rix Gray, in the collection of the British Museum of Natural History (London) 

 and particularly laid stress on the presence of parenchymal hoxastcrs with a 

 considerably elongated main axis, as distinguishing this species from the doubt- 

 less closely allied A])hrocallistes hocagei Perc. Wright. I have found that in 

 this latter species the parenchymal hoxasters are mostly without a considerably 

 elongated main axis and that it posesscs small disco-hexasters. 



Also in the Indoceanic specimens of AphrocalUstes heatrix Gray, brought homo 

 by the " Investigator," the hexasters with a diiferentiatcd, strongly elongated 

 main axis are apparently more numerous than the other hexastor-forms, which 

 latter are subject to considerable variations. The elongated hexasters are the 

 most conspicuous microsclores. They differ considerably in shape and are con- 

 nected in various ways by transitional forms with the normal, regular oxyhex- 

 asters which have 4-G equally long oblicjuely diverging branch-rays on each one of 

 the short main-rays (pi. XV, f. 5). It is to be remarked that all these hexasters 

 have pointed branch-rays and are true oxyhexasters or heraioxyhexastors. There 

 are no such claw-bearing onychasters among them as in AphrocalUstes ramosus, 

 described on p. 93. 



I think it most probable that the " syngramme " oxyhexaster-forms with a 

 differentiated, mostly elongated main-axis have been phylogenctically developed 

 from ordinary, regular " synstigme " oxyhexasters with equal axes. Thus 

 considering the former as derived from the latter, I will describe the regular 



• Phil. Trans, Eoy. Soo., Vol. 159, p. 713. 

 t Quart. Journ. Micr. Soi. 1870, p. 78. 

 X Monthly MicroBO. Journ. 1870, p. 248. 

 § " Challeuger Uozactinellida p. 2'il pi. 84, f. 9, 10, and Abb. PreasB. Ak. 1886, p. 7S. 



