Tornaria and Actinotrocha of the British Coasts

Abstract

THREE species of Balanoglossus are known to occur on the shores of North-West Europe. Balanoglossus kupfferi was taken by Willemoes Suhm at Helleback, in the Sound, that is, on the coast of Zealand (Zeit. f. wiss. Zool. vol. xxi. 1871); Balanoglossus salmoneus, Giard, and B. rebinii occur, according to Mr. Bateson's last paper in the Quarterly Journal of Microscopical Science, at Concarneau, in Finistère, and I believe also at the Channel Islands. But no Balanoglossus has yet been found on the shores of Britain. It will therefore be of some interest to British naturalists to learn that in August 1884 I obtained in the townet a larva which seemed to possess the distinctive characters of Tornaria. I had not leisure at the time to study the specimen with much attention, but I made a hurried sketch of it, which shows the presence of two parallel longitudinal bands of cilia anteriorly, and a single transverse band posteriorly. At the posterior end is a conical protuberance resembling the adhesive organ described by Bateson in his creeping larva. The position of the mouth was not ascertained, but was probably between the two anterior bands of cilia. The water vessel and tuft of cilia at the apex of the præoral lobe were not observed. This larva may not have been Tornaria, but I think it really was that form; and naturalists who are spending an autumn holiday at the seaside would probably, if they undertook the search, succeed in finding Balanoglossus in the littoral sands, and its larvæ in the shore waters.