REPORT ON THE CRINOIDEA. 271 



Quoy and Gaimard, which Miiller had identified with Asterias (Actinometra) multi- 

 radiata owing to their having not three but two palmars with the axillary a syzygy ; 

 though he called them Alecto on account of the symmetrical distribution of the 

 ambulacra on the disk of one specimen. 1 



In fact, the French authors seem as a rule to have only quoted MuUer's complete 

 Memoir " Ueber die Gattung Comatula, Lam., und ihre Arten " when dealing with 

 species which were not described by him in either of his two preliminary communications 

 of 1841 and 1843 respectively. They recognised that the Alecto ivahlbergi of 1843 

 was in 1849 transferred by Miiller to Actinometra; but they quite ignored the fact that 

 he also transferred Comatula rotatoria, Lam., to the same generic type, although it was 

 described as an Actinometra on the very same page (256) of the final memoir as Comatula 

 (Actinometra) ivahlbergi, and they simply refer to it as Alecto rotalaria, Miiller, 1843. 

 The French authors then recognised four species of Actinometra; but only one of these 

 (Actinometra ivahlbergi) was understood by them in the same sense as it had been by 

 Miiller. One of his species was restored by them to Comatula,; while, on the other 

 hand, they retained in Actinometra a type which he had erroneously transferred back again 

 to Alecto. They also regarded the Asterias pectinata as a distinct species, instead of classi- 

 fying it with Comatula Solaris, Lamarck. This course is likewise adopted in the following 

 pages, though the two forms are not placed in different genera, as was done by Dujardin 

 and Hupe, but in one only, viz., Actinometra, just as they appear in Muller's memoir. 



Nearly twenty years elapsed after Dujardin and Hupe wrote before the genus 

 received much further notice. Isolated species were described by Bohlsche and Grube 

 respectively, but no formal definition of its characters was ever published. Dr. Liitken, 

 however, had the opportunity of examining a large number of Comatulse which were 

 collected in the Eastern Archipelago for the Godeffroy Museum ; and he was led to the 

 conclusion that the essential character of Actinometra, as distinguished from Antedon, is 

 the excentric position of the mouth, 2 and that the number of ambulacra reaching the 

 peristome is a character of no importance whatever, instead of being one of generic 

 value, as Miiller had supposed. Liitken further discovered that the proximal pinnules 

 of all the exocyclic Comatulse are provided with a terminal comb (PI. LIII. figs. 3-6 ; 

 PI. LVI. figs. 2, 4 ; PI. LXIII. figs. 5,7; PI. LXV. fig. 7 ; PI. LXVII. figs. 2, 4 ; 

 PI. LXVIII. fig. 3), but that this is absent in the endocyclic species. The constant 

 association of these two characters enabled him to recognise Actinometra as a good 

 generic type ; and various species of the genus were distributed from the Godeffroy 

 Museum bearing Liitken's MS. names. Unfortunately, however, he was prevented by 

 other engagements from ever publishing his descriptions of these species, or even a 

 precise diagnosis of the genus. 



i Abhandl. d. k. Akad, d. Wits. Berlin, 1847 [1849], p. 261. 



2 See his Note in Tram. Linn. Soc. Lond. (Zool.), ser. 2, 1879, voL ii. p. 18. 



