34 



structure of the larva, the changes undergone during metamorphosis, 

 and the structure of the newly metamorphosed Phoronis, and with 

 a view to completing it after all these years I had already' procured 

 and examined carefully many shells got from trawlers and from 

 our dredging trips, and I can assure Dr. Harmer that the creature 

 is not so common as his discovery might lead him and others to 

 suppose. 



Actinotrocha branchiata. — The larva was discovered before 

 the adult ; it was one of the many forms found by J. Muller*^ by 

 the use of a plankton net at Hehgoland. He called the larva 

 Actinotrocha branchiata, but he thought it was an adult and belonged 

 to the Turbellaria. Since its discovery by MiUler it has been 

 found at several places on the British coasts of the North Sea. 

 There is Uttle doubt that the Actinotrocha foimd by Cobbold 

 near Portobello, in the Firth of Forth, was this species, for it has 

 often been obtained in the Forth since. Cumiingham f found it 

 in Sei)tember, 1883, a little to the north of Cromarty Firth. I { 

 netted many specimens in Sullom Voe, Shetland, in the beginning 

 of August, 1891. 



In the St. Andrews region it has been procured from East- 

 haven, near Carnoustie, north of the Firth of Tay, to the Firth of 

 Forth. It was first observed in 1888, was scarce in 1889, but during 

 the summer of 1890 it occurred in great profusion in St. Andrews 

 Bay ; in 1891 and 1892 it was again far from plentiful and late 

 in appearance. In 1890 the young stages were found at the 

 surface in July in great quantit3\ During August the supply 

 gradually dechned, but a few were still forthcoming in September 

 and even October. The young Phoronis was found in small 

 numbers in July, and was quite common in August and 

 September. The older larvae sink, and are found ^ith the young 

 Phoronis at the bottom. 



Off the Northumberland coast the larva has been found in 

 small numbers in Juh^, August and September from the neighbour- 

 hood of the Fames to Newbiggin,§ and m large numbers on July 

 24th, 1899, about a fathom from the surface, about five to six 

 miles north-east of CuUercoats, in 23-26 fathoms. || 



* 1846. Miiller's ArcMv. 



t 1886. Nature, v. 34, p. 361 J 1891. Xature, v. 44, p. 344. 



5 Rep. Dove Marine Laboratory, Xew Ser., 11, pp. 66-68, 1913. 



II Rep. Dove Marine Laboratory, 1899, p. 58. 



