44 PROCEEDINGS OF THE ACADEMY OF [Feb., 



I soon found that the classifications of the Ophiuroidea hitherto pro- 

 posed were very unsatisfactory. Indeed, their imperfectness became 

 a haunt to me; so I determined to devise a new classification of 

 my own. 



For this purpose, I have dissected representatives of as many 

 genera as were accessible; and the following are some of the more 

 important results obtained: 



A. Morphological. — Those forms that have arms, capable of 

 being vertically coiled, have a very compact oral skeleton (the 

 adoral shields are entirely proximal to the oral shield, being firmly 

 united to it; the oral frames are very stout, those of the same radius 

 being firmly joined together; the peristomal plates are entire and 

 more or less soldered to the oral frames, etc.), and very short, stout 

 vertebrae, of which the articulation is streptospondyline, with a 

 very rudimentary, or no articular peg. More or less divided ver- 

 tebrae are found only in certain genera with horizontally flexible 

 arms; such vertebrae are of two kinds, those which are divided into 

 halves by a single fusiform pore (found in forms in which the dorsal 

 side of the arms is more or less unprotected) and those in which the 

 two halves are separated by a series of small pores (found in forms 

 with the dorsal side of the arms entirely protected). Forms with 

 •quadrangular and stout teeth have oral frames with well-developed 

 lateral wings for the attachment of voluminous masticatory mus- 

 cles, etc. 



B. Systematic. — Astroceras, Trichaster and Euryala have a certain 

 common structure, by which they may be distinguished from either 

 Aster onyx or Asteroschema; Astrotoma and its allies have certain 

 distinctive characters in contrast to Asteroporpa, Astrochele, Gor- 

 gonocephalus, Astrocladus and their aUies; the Amphiuridae (emend.) 

 and the Ophiotrichidae are intimately related by their internal struc- 

 ture; ^'Ophiactis" pars, i.e., my Amphiactis, is a connecting link 

 between the Ophiacanthidae and Amphiuridae; the Ophiolepididae, 

 Ophiodermatidae and Ophiocomidae form together another compact 

 group; my Ophiochitonidae are not referable to Amphiuridae (emend.) 

 but are very near the Ophiodermatidae and Ophiocomidae; Ophiopsila 

 is, as a matter of fact, a near ally of the Ophiocomidae; "Ophioconis" 

 pars, i.e., my Ophiuroconis and Ophiurodon, and "Ophiochceta" 

 pars, i.e., my Ophiurochata, are perfectly distinguishable from 

 Ophiolimna (emend.), by their internal structure, etc. 



Prefixing so much, I now proceed to the. exposition of my views, 

 leaving them to be judged on their merits. 



