196 



THE VOYAGE OF H.M.S. CHALLENGER. 



leaving his readers to determine the real points of difference between his various species. 

 For this purpose I have analysed his descriptions of Comatula milberti and of Comatula 

 jacquinoti respectively, with the following result : — 



Comatula milberti. 



Twenty-five to thirty cirri of thirty-five spiny joints. 



The spine "quer absteht." 



First radials " ausserst niedrig." 



Arm-joints "niedrig." 



Syzygial interval eight or nine joints. 



The second, third, and fourth pinnules are "die 



grossten." 

 Colour, — brownish-black. 

 Spread approaching 2 feet. 



Comatula jacquinoti. 



Twenty-two cirri of thirty-five spiny joints. 



The spine is " vorwarts gerichtet." 



First radials "sehr niedrig." 



Arm-joints " niedrig." 



Syzygial interval three to six joints. 



The three to four first pinnules are " starker." 



Colour. — brownish-black. 

 Spread approaching 2 feet. 



The preceding table shows that the differences between Comatula milberti and 

 Comatula jacquinoti, as described by Midler, are in reality exceedingly slight. The 

 number of cirrus-joints, the characters of the radials and of the arm-joints, the colour, and 

 even the size are respectively identical in the two types. Comatula milberti has twenty- 

 five to thirty cirri with the spines transverse, whde in Comatula jacquinoti there 

 are twenty-two cirri with the spines directed forwards. In Comatula milberti the 

 syzygial interval is eight or nine joints, and the second, third and fourth pinnules are 

 the largest, whde in Comatula jacquinoti the syzygial interval is three to six joints and 

 the first three or four pinnules are " starker." Neither of these characters, however, nor 

 even the combination of them, can be regarded as of specific value, especially when we 

 remember that each of Midler's species was based upon a single specimen. That of 

 Comatula jacquinoti had been obtained at Ceram by the expedition of d'Urville in the 

 "Zelee" (1841), whde the form which Midler described under the specific name milberti 

 had previously received it from Valenciennes in honour of M. Milbert of New York, who 

 had given it to the Paris Museum ; and it was possibly for this reason that the type was 

 labelled as coming from North America. Under these circumstances Valenciennes, and 

 after him Midler, were perhaps a httle predisposed to regard it as distinct from the 

 Comatula jacquinoti of Ceram, which Midler described along with it and in such nearly 

 identical terms. I feel quite confident, however, that Milbert's specimen was not obtained 

 anywhere on the Atlantic coast of North America. I have seen nothing like it among 

 the West Indian Comatulge dredged by the "Blake"; while the only species of Antedon 

 which have been found on the Atlantic coast of North America are Antedon tenella and 

 perhaps Antedon eschrichti (Stimpson). All its characters are those of the species of 

 Antedon which inhabit the Eastern Seas, where the type has been obtained at various 

 localities from the Mergui Archipelago to Eastern Australia ; and I have little doubt that 

 Mdbert's specimen had been brought to America from somewhere within this region. 



