A MONOGRAPH OF THE EXISTING CRINOIDS 427 



Dr. P. H. Carpenter, in 1879, wrote that in Actinometra multifida, the type of 

 which he had personally examined in Paris in the autumn of 1876, the tertiary arms 

 borne by the palmar (IIIBr) axillaries may divide again several times. In every 

 case there are only 2 segments between each division, and all the successive axillaries, 

 like the palmar axillaries, have no syzygies. He also observed that the interbrachial 

 perisome contains numerous small calcareous plates. 



In the same memoir he wrote that the Challenger collection included 2 very ab- 

 normal species of Actinometra. The rays divide three times, and the first 2 segments 

 (distichals) of each of the 10 primary arms are united by ligaments only, like the 

 second and third radials. The third or axillary distichal bears the secondary arms, 

 which consist of 1 axillary segment only, which is primitively double, being made up 

 of 2 parts united by syzygy. The first joints of each of the ultimate arms borne by 

 this axillary agree with it in being syzygial segments. These species are Comaster 

 novae-guineae and C. distincta. 



In 1881 Carpenter redescribed the type specimen of Alecto novae-guineae and de- 

 scribed in detail a specimen from Jobie which he identified as Actinometra typica, 

 referring it to Lover's species. As a synonym of the latter he cited the Actinometra 

 stellata of Liitken, of which he had examined some duplicates distributed by the 

 Godeffroy Museum. He mentioned that during his visit to Copenhagen he found 

 that Liitken had already come to the conclusion that his stellata was the same as 

 Lov6n's typica. He discussed the proximal syzygies in this species at considerable 

 length and gave a summary of its distinctive characters. He said that no 2 speci- 

 mens of this type which he had seen are quite alike, but they pass iuto one another 

 so very gradually that it is practically impossible to separate them. He mentioned 

 some large specimens from Cebu in the zoological museums at Dresden and at Vienna, 

 and one dredged near Fiji by the Challenger. 



He considered typica as the nearest ally of novae-guineae, but differing in the 

 stellate centrodorsal with few or no cirrus sockets, and in the much longer and more 

 slender segments of the terminal pinnules, which have the large lateral spines occur- 

 ring on both sides instead of being almost entirely limited to the outer side of each 

 segment. 



Prof. F. Jeffrey Bell in 1884 recorded a number of specimens of this species which 

 had been collected by the Alert in the Torres Straits region under the name of Acti- 

 nometra multifida. He also described as a new species Actinometra variabilis based 

 on 4 specimens from Thursday Island which do not differ in any way from others 

 which he referred to multifida. Under the name multifida he included a specimen of 

 Comanthina schlegelii from the Percy Islands. 



In 1884 Carpenter mentioned the occurrence of syzygies between the elements 

 of the IBr series in novae-guineae and typica, and the anomalous development of this 

 syzygy in typica. He also noted the extreme reduction of the centrodorsal in stellata. 

 He divided the species of "Actinometra" into 8 groups, one of which he called the 

 "Group of Actinometra typica." 



In 1888 Carpenter redescribed Actinometra typica on the basis of the single 

 specimen secured by the Challenger. His description differed only slightly from that 

 which he had published in 1881 . The only additional features he mentioned were that 



