A MONOGRAPH OF THE EXISTING CRINOIDS 201 



penter's Actinometra robustipinna from the Moluccas, in the type of my Himerometra 

 robustipinna from Albatross station 5165, hi the type of Hartlaub's Antedon kraepelini 

 from Akyab, Burma, and in Reichensperger's specimens from Ceylon. In the two 

 specimens of Bell's Antedon inopinata from the Macclesfield Bank the distal ends of 

 the segments of the enlarged proximal pinnules are very slightly swollen, while in 

 Hartlaub's three specimens of Antedon crassipinna from Amboina and in Reichen- 

 sperger's specimens from Little Kei the distal ends of the segments are thickened and 

 overlap the bases of the succeeding segments. 



In all cases P D has about 20 segments (17-20), except that in one of the specimens 

 from Little Kei described by Reichensperger it has 22-24 segments. This specimen 

 would seem to show an approach to H. magnipinna. 



History. The history of this species is curiously involved. It was first described 

 from a much mutilated specimen from the Moluccas as a species of Comasteridae, 

 Actinometra robustipinna, by Dr. P. H. Carpenter in 1881. 



In the Challenger report on the comatulids published in 1888 Carpenter inserted 

 Actinometra robustipinna in the key to the species of the Parvicirra group of Actino- 

 metra where it was given as having IIIBr 4(3+4) series, but no IVBr series, 30 or 

 more cirri of (by inference) 15-20 segments, and the pinnules on the division series very 

 large and stout. In discussing Comanthus trichoptera Carpenter said that robustipinna 

 resembles it in the presence of a large number of cirri, but is readily distinguished by 

 the great size of its first three pinnules. 



In 1890 Dr. Clemens Hartlaub described Antedon kraepelini from Akyab, Burma, 

 and Antedon crassipinna from Amboina, including with the latter as conspecific a speci- 

 men in the Hamburg Museum from Cochinchina. He redescribed these two species in 

 greater detail and figured them hi the following year. In the key to the species which 

 he discussed in his memoir he placed Antedon kraepelini, paired with A. martensi, under 

 the heading IIIBr 2, and P D very stout. But he mentioned in the key that in kraepelini 

 the outer IIIBr series are often 4(3+4). He placed Antedon crassipinna under the 

 heading IIIBr series 2 and 4 (3 +4), together with Antedon bipartipinna (=acuticirra). 

 His description of Antedon kraepelini immediately follows that of A. martensi, but 

 the description of Antedon crassipinna is many pages farther on, separated from the 

 description of A. kraepelini by the descriptions of Antedon brockii, A. affinis, and A. 

 nematodon and a discussion of A. ludovici. In his description of Antedon kraepelini 

 he said that the inner IIIBr series are always 2, but the outer are often 4(3+4). He 

 seems to have attached no importance to this in A. kraepelini, but in his account of A. 

 crassipinna he discussed at considerable length the curious arrangement of the IIIBr 

 series which are 2 internally and 4(3+4) externally. 



In his remarks under Antedon kraepelini Hartlaub said that the short and rapidly 

 tapering arms are hi strong contrast to the central portion of the animal, which has a 

 large centrodorsal and relatively stout IIBr series. This curious form while giving 

 an individual comatulid a very characteristic appearance, seems to be nothing more 

 than the result of somewhat abnormal development. Individuals of this nature are not 

 infrequent in Heterometra reynaudi at Ceylon. 



In 1894 Prof. F. Jeffrey Bell described Antedon inopinata from the Macclesfield 

 Bank. This new species he placed in Carpenter's Granulifera group, which Included 



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