Anatomical Nomenclature of Echinoderms. 5 



supites^ as if its homology were quite undoubted ; and it is 

 not surprising tliert'fore that its coexistence witli under-basals 

 in that type shoukl have driven Neuniayr to the conclusion 

 that something was wrong. Salenia has a dorsocentral only. 

 Marsupites has a dorsocentral and under-basals. The An- 

 tedon-\ii\-yvi has a dorsocentral at the bottom of the stem, a 

 centro-dorsal at the top, and under-basals resting upon it. If 

 these facts be carefully borne in mind, much that has seemed 

 so obscure both to Xcumayr and to his predecessors receives 

 its proper explanation. 



3. Basals and Under-hasals. 



The nomenclature of the plates forming the dicyclic base in 

 many Crinoids is still somewhat wanting in uniformity and pre- 

 cision. Twelve years ago* I pointed out that the so-called 

 parabasals of the dicyclic Crinoids are the real homologuesof the 

 basals in the monocyclic forms, the lower ring of plates in the 

 dicyclic Crinoids being an additional element in the calyx. 

 I proposed to call the latter " under-basals," retaining the 

 name *' basals " for the plates immediately below the radials, 

 bothin the dicyclicandin the monocyclic forms. Every scientific 

 palaeontologist f i^ow admits that the latter plates are homo- 

 logous throughout the whole series of Crinoids, and the pro- 

 posed change in tlie nomenclature has been adopted by the 

 leading writers on Crinoids in this country, Australia, Canada, 

 the United States, France, and Switzerland, and also by 

 Ludwig, the chief German writer on Echinoderms. Zittel f, 

 however, wiiile accepting both the homology and the term 

 under-basals, or, as he put it, " infrabasals," believed that 

 the use of the name basals for the upper plates of the dicyclic 

 base would lead to confusion ; and so he retained for them the 

 JMullerian name parabasals, thus giving two different names 



• Ihid. pp. 3G6, 367. 



t Walther, writing in 1886, liomologized the iufrabasals of Dicyclica 

 with the basals of Slonocyclica (" Untersuchungen liber den liau der 

 Crinoiden,'' Palaeontographica, 1886, Bd. xxxii. p. 189). His couchisious, 

 however, wei'e largely based upon questions of transcendental morphology 

 which were suggested by his study of the Pentacrinoid larva of Antedon, 

 Among them are his remarkable identification of the live primary ten- 

 tacles of the larva with the clavicular pieces on th^j radial axillaries of the 

 adult, which has already been noticed in this Journal (ser. 5, vol. xix. 

 p. 88) ; and as liury has demonstrated the presence of under-basals in the 

 larva, which were overlooked by Walther, as by all his predecessors, 

 "Walther's views respecting the homologies of the basals of the adult 

 Antedon and other apparently monocyclic forms are uo longer tenable, as 

 he will no doubt admit when he next writes upon the subject. 



X ' llandbuch der Palpeontologie,' Bd. i. pp. 827, 328. 



