594 Mr. W. K. Fisher — Notes on Asteroidea. 



reduced than in Anasterias, the upper marginal plates being 

 absent, except as rudiments distally. It is covered by a thick 

 dermis and bears large, wide, felipedul pedicelhirise/' Kcehler 

 {J.OC. cit. p. 16) accepts the genus and adds a new species — 

 F.jofrei. 



Ludwig {loc, cit. p. 42) characterizes Anasterias as 

 follows : — Five-iayed Asteriidre with monacanthid adanibu- 

 lacrals ; antiambuh'icral arm-skeleton reduced to lateral 

 transverse bars ["Spangen"] and isolated dorsal pUites. 

 He divides the species into two principal groups : (a) The 

 bars [wliich abut on the adanibuhicrals] are formed of only 

 two skeletal pieces, a reduced supert)- and inferoinarginal, 

 the latter carrying an interomarginal spine — A. cMrophora, 

 A. lactea, A. perrieri. {h) The lateral bars are composed of 

 more than two pieces — A. belgicce^ A. studeri. 



In his description of cliirophora, Ludwig states tliat the 

 lateral skeleton is composed of tliese cross-bars, each witli 

 two small plates {loc. cit. p. 48, fig. 1, p. 49, tig. 2). The 

 plate adjacent to the adambulacrals has its longer axis 

 lengthwise of the ray, and represents the inferomarginal, 

 while the outer of the two has its long axis transversely 

 oriented and represents the superomarginal plate. Moreover, 

 this arrangement of plates in longer or shorter cross-bars is 

 characteristic of the other species of the group known as 

 Anasterias (^=- Ly sasterias) . 



Kcehler tinds in his Pcedaaterias jo^rei {loc. cit. p. 32) 

 cross-bars of several pieces, as in Anasterias belc/icce, Ludwig 

 [loc. cit. pi. vi. fig. 62), but thinks that the su})eromarginals 

 are not to be found in these arcs. Rather, they are one or 

 two plates, in the iuterbrachial angle, above the first infero- 

 marginals, and quite independent of the little cross-tiers. 

 The sui)eromarginals would therefore be lacking in the ray. 



In Anasterias tenera, Kcehler, in which the marginals are 

 more strongly developed than in other species (although the 

 abactinal s-keleton is normally reduced), these lateral cross- 

 bars are characteristic. In the specimen which I have 

 examined (no. 1842, Museum of Comparative Zoology) these 

 arcs consist usually of two, sometimes of three plates, but the 

 outer, usually sjnuiferouSj superomarginal is oriented trans- 

 versely, and the inner, inferomarginal, more longitudinally, 

 as in chirojyhoraj laetea^ and jt)em'en'. 



Koehler may be correct in his interpretation of the lateral 

 plates oi joffrei and belgicce^ but I think Ludwig is correct in 

 considering as superomarginal the outer of the two lateral 

 jjlates of chirojjhoraf lactea, and perrieri. 



