INTBODUCTION. 9 



the Crinoids ; a Becond Class, the Actinozoa, with i\w> orders, the Urchins 

 and Asterids (including Ophiurids); and a third Class, the Scytodermata, 

 with two orders, the Eolothurians and the Sipunculida After the publi- 

 cation of his Morphologie, Leuckart himself does not Beem to have laid 

 u r r«-:i t stress upon -nine of bis suggestions for new classification. In his 

 Report for 1848 to 1853 he onlj refers incidentally to the name Pelmato- 

 zoa, and divides the Echinoderms into, I. Holothurida, 2. Echinida, 3. Aste- 

 rida, 1. Ophiurida, 5. Crinoidea. In his Reports for L 854-55 and for 1856 

 the same nomenclature is followed. In bis Report for 1857 he speaks of, 



1. Scytodermata, 2. Actinozoa (Echinida, Asterida, Ophiurida), 3. Crinoidea. 

 For 1858 liis Report corresponds with that of 1857, and it is only in his 

 Report for 1859 that we find the name Pelmatozoa reappear, ten years 

 later than its first introduction. In liis Report for 1859 we find the 

 Echinoderms divided into, 1. Scytodermata, 2. Actinozoa, 3. Pelmatozoa. 

 In 1860 he again drops the name Pelmatozoa, and we find. I. Scytodermata. 



2. Actinozoa. 3. Crinoidea. The same nomenclature occurs again in his 

 Reports for 1801 and 1802. and for 1803. In that for 1864 and 1865 

 we find the nomenclature as stated in the Report for 1859, Pelmatozoa 

 being again introduced. Then for a series of years. 1800 and 1807, 1868 

 and 1869, 1870 and 1871. and JS72 to 1 S7-3. he speaks in those Reports 

 of Pelmatozoa ; while in the last Reports by Leuckart. in Wiegman's 

 Archiv. he again, 1870 to 1S79, introduces, 1. Scytodermata, 2. Actinozoa, 



3. Crinoidea. 



The name Pelmatozoa was not adopted by any writer on Crinoids ex- 

 cept, as Carpenter states, by Sir Wyville Thomson* in the Syllabus of liis 

 Lectures ; and, as is seen from what has preceded, Leuckart himself used 

 indiscriminately Crinoidea or Pelmatozoa. It is therefore not surprising 

 that Roemer should not have adopted Leuckart's name, and should have 

 continued to retain the name of Crinoids for the group as a whole, al- 

 though recognizing the great distinction existing between the Brachiate 

 Crinoids, the Blastoids, and the Cystids. 



The confusion which has arisen in the nomenclature of the primary di- 

 visions of Echinoderms illustrates the difficulty of attempting to retain old 

 and familiar names as descriptive of groups when limited by more recent or 

 more extended knowledge, or by applying to these older names ideas of 

 nomenclature entirely unknown at the time they were first adopted. To 



* Syllabus of Lectures on Zoology, Edinburgh, 1878. 



