REPOET ON CEPHALODISCUS DODECALOPHUS. 



DESCRIPTION. 



The description of this peculiar type may be taken under the following heads : — 



I. The House or Ccenceeium ; 

 II. The Poljrpides, including — 

 a. Buccal disk. 

 h. Branchial plumes. 



c. Digestive system. 



Mouth. 



Pharynx. 



GEsophagus. 



Stomach. 



Pyloric chamber. 



Intestine. 



Food. 



d. Body-wall and body-cavities. 



c. Muscular system and pedicle. • 



f. Nervous system. 



g. Eeproductive organs. 

 h. Buddins;. 



III. General Remarks and Homologies. 



I. CCENCECIUM. 



At first sight the flexible coenoecium might be mistaken for a sea-weed, since it is 

 composed of a much branched fucoid tissue, tinged of a pale brownish hue, and semi- 

 translucent. Moreover the whole surface of the thickish stems is hispid with long 

 tapering spinous processes or fimbriae of the same tough secretion, and perforated 

 here and there by somewhat large apertures with smoothly rounded edges. A more 

 minute inspection reveals various opaque bodies in groups in the interior of the branches ; 

 and the appearance of these suggested the relationship of the structure to the Polyzoa or 

 Ascidians. When first seen in the Strait of Magellan it was supposed, Mr. Murray 

 observes, to be a Compound Ascidian. After having subjected it to more careful examina- 

 tion on the completion of the voyage, the late lamented Professor Busk, however, pointed 

 out its distinction from the ordinary Polyzoa ; while Professor Herdman, as already 

 mentioned, was satisfied it did not fall under the Ascidians. 



The house or coenoecium of Cejjhalodiscus dodecalophus^ (PI. I. fig. 1) consists of 



' Kt(pa'Kvi, head ; o/axo?, disk ; tuiixa, twelve ; Xoipoj, plume. 



