338 Prof. M‘Intosh on Cephalodiscus, a new Type 
73° 53’ W. Depth 245 fathoms. Bottom-temperature 7°°7C. 
Sea-bottom composed of mud, which seemed to be fairly rich 
in other groups. 
At first sight the flexible structure may readily be mistaken 
for a seaweed, since it is composed of a much-branched fucoid 
tissue tinged of a pale brownish hue and semitranslucent. 
Moreover the whole surface of the thickish stems is hispid 
with long spinous processes 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 relation- 
ship of the structure to the Polyzoa or Ascidians. Prof. Busk, 
however, pointed out its distinction from the ordinary Polyzoa, 
and Prof. Herdman had stated that it was not an Ascidian. 
The following description is drawn up from a few fragments 
and three excellent slides mounted by Prof. Busk. Other 
points will probably be made out on the arrival of the larger 
examples, which have not yet reached me. 
The ccencecium or polyparium of Cephalodiscus dodecalophus* 
consists of thickish, irregularity rounded or flattened stems 
of the consistency of soft seaweed, and having a slight 
lustre like the semitransparent tubes of many annelids. ‘The 
stems have a diameter varying from 4 or 5 millim. to double 
or treble that breadth in the flattened expansions; but the 
general size of many of the branches is nearly uniform. The 
main trunks seem to have arisen from submarine objects, such 
as stones or sponges ; but instead of standing erect like soft 
Gorgonians, to which the inosculations of the branches give 
them some resemblance, they appear to have been more or less 
horizontal, since pillars of the tissue occasionally pass, like 
aerial roots, from the underside to the plane of attachment. 
The surface of the branches is everywhere studded with 
elevations and ridges, which terminate in long spines—simple, 
bifid, trifid, or multifid, and here and there bending down- 
ward to join the main stem, so as to form loops or arches, or 
inosculating with adjacent spines. Some of the spines are 
very large, and project far beyond the others, and occasion- 
ally they occur in groups. They generally taper a little 
towards the tip, which is often attenuate and of a deeper 
brownish hue than the rest of the coencecium. ‘The tips of the 
branches often show longer spines variously divided. The 
irregularity in regard to the distribution of the spines recalls 
the processes on the curious Chondrocladia, though it is much 
more marked than in the latter. All the spines are hollow 
* kepadr, head; dicxos, disk; d@dexa, twelve ; Addos, plume. 
