with descriptions of new Species. 181 



some way within the horny tube. The polype in short had been 

 absorbed. Many similar cases have occurred to me. 



The newly-formed polypes are of a most delicate whiteness, 

 and are beautiful objects, especially when they appear on an old 

 and worn polypidom, reminding one of frail blossoms bursting 

 forth from a bare and rugged stem. They are developed at the 

 ends of the branches and are non-retractile. The body is more 

 or less ovoid, and is produced above into a kind of snout which 

 bears the mouth. This portion is capable of much elongation 

 and contraction, and possesses great mobility. From the pecu- 

 liar lined appearance which it presents in certain lights, I am 

 inclined to believe that it is furnished with an apparatus of 

 muscles. The mouth is connected by a short passage with the 

 stomach. This organ is a well-defined cavity, elongate-oval in 

 form, which tapers off below, and is prolonged into a canal which 

 passes down the centre of the pulp. This canal like the stomach 

 itself is very clearly defined. The polype-head is supported on a 

 fleshy neck, to the base of which the horny polypidom extends. 



The walls of the stomachal cavity and the central canal are 

 covered with a complicated web of anastomosing vessels, from 

 which simple vessels seem to pass off to the sides. This vascular 

 structure is, so far as I know, unique amongst the Hydroid Zoo- 

 phytes, and it gives a veiy marked and peculiar appearance to the 

 polypes of the Cordylophora. 



The arms are scattered over the body, filiform, and roughened 

 with granules, which are arranged in regular nodules. They 

 present a very interesting structure. They are distinctly tubu- 

 lar and prettily encircled at intervals by rings, which are no 

 doubt muscular bands, and which are all connected together by 

 longitudinal fibres, running the entire length of the arm, and 

 prolonged at the base into the body. Upon this structure is de- 

 pendent, in great part, thef remarkable power which the polype 

 possesses of elongating and shortening its tentacles. At times 

 they are so much extended as considerably to exceed the entire 

 body in length, and in this state are attenuated into most deli- 

 cate filaments. When contracted they appear corrugated and 

 comparatively thick, and the muscular rings are pressed toge- 

 ther. I have seen the arms, when extended, fully six times as 

 long as in their contracted condition. 



The polype of the Cordylophora is a singularly beautiful object 

 when its tentacula (some twelve or fourteen in number) are all 

 elongated, floating like slender threads through the water, and 

 waving to and fro with its every slightest movement. 



Reproduction of Cordylophora. 

 The Cordylophora is propagated, like the Sertularian zoo- 



