OPHIOMASTIX JANUALIS. 15 



under a lens, finely grooved ; lengths (5th joint). 2.3. 2. 1.2. Tentacle- 

 scales usually two. of which the oviter is nearly oval, the inner small, 

 narrow, and tooth-like. Color, in alcohol : chocolate brown, dappled 

 with yellowish. 



Mexillones. Bolivia ; Captain Putnam. 



As to the genus of this specimen, it may be called a spiny OpMocoma, 

 or an OpMomadix wanting the club-shaped arm-spine. Miiller & Tros- 

 chel, in characterizing OpMomastix, say (Syst. Asterid., 107), "Disk 

 beset with scattered spines. . . . On the arms, above the spines, club- 

 shaped bodies running out at their ends into several projections " ; and 

 their original. 0. annuhsa, lias a fine imbricated scaling, from which 

 stand out little naked radial-shields. Liitken (Addit. ad Hist. Oph., Pt, 

 III. p. 26) has shown that the club-shaped spine is not a constant fea- 

 ture in the genus, which therefore is hardly to be set off from Ophiocoma, 

 and that, moreover, the disk maybe beset either with spines of various 

 sorts, or with spines and grains. With the addition of this species, his 

 view of the genus would stand thus : — 



A Disk smooth or with very few short spines, O. venosa Pet. 



B. Disk closely beset with grains anil moderately long spines, O. mixta Ltk. 



C. Disk densely beset with very ?hort spines, O. asperula Ltk. 



t> Tv- i \ .1 • i i . -.i i »\ • ■ ( ' '■ anmdosa M. T. 



D. Disk on both sides beset with long thin spines, J 



( 0. caryophyllata. Ltk. 



E. Disk beset on its upper surface, only, with slender spines ; arm-spines > n ■ ,. T 



11 . ■" * ' - O. janualts Lvm. 



all slender and tapering, ) 



The species under A, B, C, and D all have certain of the arm-spines 

 either club-shaped or forked at the end, but that under E lias no 

 thickening of these spines. 



NOTE ON NOMENCLATURE AND CLASSIFICATION. 



Dr. Liitken, in a foot-note on page 68 of his Additamenta (Part 111.1. 

 remarks : 1. That names prior to Linnaeus have no place in present 

 nomenclature. 2. That, when an author has described a species, his 

 name must always be put after that species as the authority, no matter 

 if the generic name be changed. As to the first of these propositions. I 

 may say, that Linnaeus first contrived what is called binomial nomencla- 

 ture, in which each animal has two names, the generic and the specific. 

 Consistency is the first duty of a naturalist, therefore it was the first 

 duty of the followers of Linnaeus to respect and to adopt such binomial 

 names as may be found in ante-Linnaean authors, of whom some were 

 among the most celebrated of zoologists. When, then. I find the name 

 Astrophyton costosum distinctly used by Seba (III. PI. IX.. Fig. 1. p. 16, 

 1758), and moreover an excellent figure given, I shall certainly apply 

 that name to the West Indian species to which it belongs. Did not 



