Occurrence of Halistemma in British Waters. 415 



tory, and reproductive structures are distributed. It is long, 

 very extensible and contractile, and flexible. In the specimen 

 under consideration it ends abruptly, as if a portion of it were 

 wanting. The structures which it bears are crowded together 

 at the proximal end, but occur more sparsely as we proceed 

 distally. 



The anterior part of the siphosome is covered with buds, 

 which are evidently young polypes or feeding individuals, and 

 then follow more fully matured polypes as we pass along the 

 axis. Of these polypes or feeding individuals there are two 

 incipient and nine fully developed, the former following 

 pretty closely on one another and the others at increased 

 intervals. The first distinct polyp exhibits a large basal 

 portion and a small oral portion, and at the base may be seen 

 the contracted tentacle. The full-grown polypes, in their 

 preserved condition, are all acorn-shaped, presenting a large 

 basal part, corresponding to the cup of the acorn, and then a 

 cone-shaped portion, somewhat elongated and terminating in 

 a shallow cone, in which the mouth is situated. Round the 

 basal portion the many-branched tentacle may be seen in a 

 highly contracted state. The ninth or last polyp is repre- 

 sented only by its basal portion and coiled tentacle, the larger 

 part of it having been torn off. 



The tentacles unfortunately were all in a contracted con- 

 dition, and this is to be regretted, as Hseckel, following 

 Eschscholtz and Huxley, in his new arrangement of the 

 Siphonophora, employs the characteristic appearance of the 

 terminations of the branches of the tentacles for the distinction 

 of genera. As far as I could make out, however, the tentacles 

 of the specimen exhibit the simplest form of termination, and 

 would therefore point to its belonging to the genus Hali- 

 stemma. 



Along the internodes or portions of the axis between the 

 polypes numerous other structures are distributed. Some of 

 them resemble closed polypes, some little urns, and others 

 bunches of grapes, and these seemingly represent sensory, 

 excretory, and reproductive organs. 



The closed polypes, called palpons by Hseckel, are regarded 

 by him to be sensory in function. The urns in which there 

 is a mouth or opening he considers to be excretory. The 

 cluster-like structures again are gonodendra, of which several 

 occur in each internode. 



Bracts are figured by Mr. Holt in his drawing, although 

 very sparingly. In the preserved specimen I have not been 

 able to alight on one. They arc leaf-like structures, triangular 

 in form. 



