384 ART. 2. — H. MATSUMOTO : 



Postscript. 



Recently I received Clakk's " Catalogue of Recent Oplainrans," 

 Mem. Mns. Comp. ZooL, Vol. XXV, No. 4. As this paper of mine 

 was then in press, no reference is made to it in the Hteratnre of 

 the species. My opinions or notices upon several parts of his 

 monograph have been added as foot-notes. 



General Explanation of Plates. 



PI. I, figs. 1-9 illustrate the internal stractures of the Ophmnyxina:. The peristomial plates 

 are double in Ophiomyxa australis (figs. 4 & 7) and Ophiostiha hidekii (fig. 9), one overlapping 

 the other in the latter species ; triple in Ophiodera anisacnntha (fig. 1); double or triple in Ophio- 

 hgalus gotoi (fig. 8). It is noteworthy, that the peristomial plates show a tendency to be simple 

 in younger stages, as may be seen in fig. 4, illustrating a younger siDecimen of Ophiomyxi 

 misiralis. The double or triple (at least in adult), thin, delicate peristomial plates, and not very 

 stout oral plates and frames are characteristics of the Ophiomyxinœ in. contrast to tbe Opldo- 

 byrsina', Tiichastervdœ and Gorgonocephalîdœ. The articulation of the genital plate and radial 

 shield is illustrated in fig. 1 {Ophiodera anisacaiithu) and fig. 4 [Ophiomyxa australis); it is very 

 simjjle, without any particular condyle and socket, a common character of the Phrynophiurlda 

 and Lcemophiurida. In the last two illusrations, the genital scales are seen to articulate with 

 the genital i^lates at some distance away from the outer ends of the latter, a common character 

 of the OpMomyxidœ and Asieronychina: in contrast to the Trlchasterbia:, Asteroschematinœ and 

 Gorgonocephalîdœ ; and the dorsal surface of the vertebrre (excejit the very basal ones) is rhom- 

 boidal and the wings of the same very thin on the sides, a characteristic of the Ophiomyxinœ in 

 contrast to the Ophiohyrsina;, Trichasteridœ and Gorgonocephalidce. The articular surfaces of the 

 vertebrœ are illustrated in figs. 2 & 3 (Ophiodtra anisacantha) and 5 & 6 {Ophiomyxa australis); 

 the articulation is typically zygospondyline, the umbo and knobs on the inner articular surface, 

 and the shoulder and peg on the outer, being all well developed, a character of the Ophiomyxinoi 

 in contrast to the Ophiohyrsina-, Trichasterbue and Gorgonocephalîdœ; the great size of both 

 the iipper and lower mi^scular fossœ is a character common to the Ophiomyxida' and the other 

 " common " ophiurans in contrast to the Trichasterido' and Gorgonocephalidœ. 



PI. I, figs. 10 & 11 and PI. II, fig. 1 ulustrate a vertebra of Ophiosmilax mirahilis, a repre- 

 sentative of the Ophidbyrsina'. The articulation is typically streptospondylino or saddle- shaped _ 

 a common character of the Ophiohyrsinœ, Trichasteridœ and Gorgonocephalidœ in contrast to the 

 Ophiomyxina:. The upper and lower muscular fossœ are both large, a character of the Ophio- 



