may be presumed that the species is probably C. dodccalophus. Nothing is said about males, but 

 Andersson was the first to describe the free larvae, which are ciliated planula-like organisms. 



In the same year (1903) I published a note announcing the fact that I had in my hands 

 Cephalodiscus from Oriental Seas; and in the following year (04, p. 26) I mentioned the 

 peculiarities of the remarkable male zooids found in one of these colonies. 



In addition to the papers noticed above frecjuent references to Cephalodiscus have 

 appeared in other places. Some of these are discussed in the later parts of this Report; but special 

 mention must be made here of the work of Fowler (92, 1,2), who was the first to demonstrate 

 that Rhabdoplatra, like Cephalodiscus^ conforms to the Balanoglossus-type of structure. 



II. SPECIMENS EXAMINED. 

 The material on which this Report is based consists of the following specimens: 



(I) A fragment of the original female colony of C. dodecalophus, dredged by the „Challenger" 

 in the Straits of Magellan at a depth of 245 fathoms (;= 448 M.). 



(II). C. gracilis n. sp. 



"Siboga". Stat. 89. Pulu Kaniungan ketjil, reef. [E. coast of Borneo], i Ex., §. 



(III). C. siboga e n. sp. 



"Siboga". Stat. 204. Between islands of Wowoni and Buton; Northern entrance of Buton 

 Strait, 75 — 94 Metres. Sand with dead shells. [Off S. E. point of Celebes], i Ex., cT '• 



(IV). C. levinseni n. sp. 



A specimen received from the Copenhagen Museum. Obtained in Long. i28°2o'E. Lat. 32° 10' N. 

 [Oft" W. coast of Japan, at the S. end of the Corea Strait], 100 fathoms {- 183 M.j. i Ex., 9- 



(V). RJiabdoplciira sp. 



"Siboga"". Stat. 204. Between islands of Wowoni and Buton, 75 — 94 Metres, i Ex. [This 

 specimen, found during the correction of the proof-sheets, will be described in Section XIX]. 



The specimen which I propose to call C. gracilis was found during the examination 

 of a colony of Tubucellaria sp. -), one of the Polyzoa which had been entrusted to me for 

 description. It consists of a small number of delicate, almost colourless tubes (coenoecium), whose 

 association with the Tubucellaria is probably accidental. The tubes have a prostrate habit, and 

 are supported along the greater part of their length by the calcareous branches of the Polyzoon. 

 Their appearance, as .seen with the naked eye (PI. I, fig. i) is very different from that of any 



1) -V fragment of coenoecium, without zooids, has more lecenily been found by Professor Weber in material from Stat. 204. 

 It may be part of the male colony described in this Report. 



2) The species is probably T. fusiformis D'Orb. 



