56 THE VOYAGE OF H.M.S. CHALLENGER. 



2. Antedon microdiscus, Bell. This is another species like Antedon elegans which has 

 the two outer radials united by syzygy, although they were not so described by Bell, who 

 assigned to the type a formula so unusual for an Antedon, 1 (A. 3. 3(3)), that I was led to 

 examine the spocies for myself, with the result mentioned above. His formula is defective 

 in another respect besides the all-important omission of the R; for it takes no account of 

 any arm-divisions beyond the third axillary above the radials, and could not therefore 

 apply to any species with more than eighty arms. He says, however, " probably as 

 many as 90 arms in an adult," and nine sets of quaternary arms are represented 

 in his figured specimen. They are absent, however, in one of the smaller examples 

 of his type, which for this and other reasons I am disposed to refer to Antedon multi- 

 radiata. But their presence is nowhere indicated in the formula given by Bell ; and he 

 also puts the 3 indicating the tertiary or post-palmar series in a bracket, which would 

 imply that the full number of eight series is not developed on every ray. I much doubt, 

 however, whether an example of this or of any other type will ever be found with 

 exactly eighty arms owing to the presence of forty post-palmar axillaries and none 

 beyond them ; and his formula only tells us that every individual of this species does 

 not conform to this very regular arrangement. 



Bell not only omits all reference to the quaternary arms in his better developed 

 individuals of this type, but he says of the tertiary arms that " of the three joints the 

 axillary may or may not be a syzygy." His figured specimen has the full number 

 (forty) of tertiary arms, and the axillary is a syzygy in each case. But in the smaller 

 individuals there seem to be some exceptional series of two joints only, the axillary not 

 a syzygy. This is probably the condition alluded to by Bell, but it would have been 

 better if he had described it more precisely, for a series of three joints with the axillary 

 not a syzygy is an arrangement which I have not met with in any Comatula, though it 

 is to be found in the Pentacrinidse. 



3. Antedon loveni, Bell. Bell has given the name loveni" to the form which 

 appeared as Antedon insignis in his first list f and as this is the host of Myzostoma 

 coriaceum, the name should be altered in the Report on the Myzostomida by Professor 

 von Graff. 4 On the other hand Antedon loveni of Bell's first list has been since described 

 by him as Antedon pumila. 5 



4. Antedon milberti, Mull., sp. Midler's two species, Comatula milberti and 

 Comatula jacquinoti, appear to me to be identical ; and the second name thus becomes 

 a synonym of the first. 



5. Antedon phalangium, Midler, sp. This Mediterranean species was for a long 

 time but very imperfectly known, and examples of it were described by Barrett from the 



i " Alert " Report, p. 155. 2 " Alert " Report, p. 158. 



s Proc. Zool. Soc. Loud., 1882, p. 534. 4 Zool. Chall. Exp., part, xxvii., 1884, pp. 14, 18, 40. 



6 " Alert " Report, p. 157. 



