400 Transactions of the Society. 



I have it from Mr. John Hood that the small marine species he 

 sent to Mr. Gosse in 1888 is the one which is now described in 

 this paper under the name of S. cecilia. 



Ehrenberg's figure shows a large Synch seta, with very large and 

 broad auricles, and it was not until 1894 that it was again certainly 

 identified by Dr. Levander, who found it in abundance in the open 

 sea and at various places round the coast of Finland, and has given 

 a better drawing of it in his memoir. A few years previously 

 Dr. L. Plate received some spirit material collected by Dr. Nord- 

 qvist in the Gulf of Bothnia and in the northern parts of the 

 Baltic. In this material he found a large Synchoeta fully con- 

 tracted into a ball, showing no foot at all. This Dr. Plate named 

 Synchceta apus, and described as a new species. Dr. Levander, 

 however, has proved quite satisfactorily tha,t it is no other than 

 S. baltica. 



I have considered it necessary to give this short historical sketch 

 of S. baltica in order to clear up its identity and separate it from the 

 various species to which this name has been wrongly applied. 



Dr. Levander has been good enough to send me some fairly 

 well preserved specimens of Synchceta baltica, yet they are not so 

 perfect and fully extended as one could wish. Fig. 11, pi. VI. has 

 been drawn by Mr. Dixon-Nuttall from one of these, and is suffi- 

 ciently characteristic, but should be compared with Dr. Levander's 

 sketch of the living animal. Fig. 11a represents a front view of 

 the head, which has been kindly sent me by Dr. Levander. 



The shape of the living S. baltica, according to Dr. Levander's 

 description, is bell-shaped, rounded in front, constricted below the 

 auricles, then widening again considerably in the middle of the 

 body, whence it tapers gradually to the thick foot. In the pre- 

 served specimens the posterior end of the body shows a ring-like 

 thickening of the integument from which the foot emerges ; it may 

 be, however, that this is due to the partly retracted foot, and that 

 in the living animal the body merges gradually into the foot, as 

 shown in Dr. Levander's drawing. The foot is stout, of consider- 

 able size, and carries two thick obtuse toes, well separated, in which 

 the fine canals of the foot-glands can be readily seen. The toes are 

 not pointed, but distinctly cut off, or truncate and flat at the tip. 



The ciliary wreath is of the usual type, but the auricles are 

 particularly large and very broad and clothed with long vibratile 

 cilia as is well represented in Mr. Dixon-Nuttall's figure. Four 

 frontal styles nre present as usual, the outer pair emerging from 

 triangular fleshy flaps of skin. On each side of the extreme front 

 is a tuft of fine radiating sense-hairs ; around the mouth on the 

 ventral side are the usual four setose pimples carrying each two or 

 three stiff hairs. 



The dorsal antenna is situated on an eminence in its usual 

 position above the eye, and the lateral antennas emerge low down 

 in the lumbar regions and a little on the ventral side. 



