TH EC ACER A. 575 



This curious animal, an inhabitant of the coasts of 

 France and Norway, was first observed in Britain at 

 Campbeltown in Argyleshire (E.F,), and has since been 

 taken by Mr. Alder and INIr. Landsborough elsewhere in 

 the Clyde district ; in Cornwall by Mr, Peach ; and on 

 the Cork coast, by Professor Allnian. It inhabits the 

 margin of the littoral zone. 



THECACERA, Fleming. 



Body oblong, smooth. Tentacles clavate, pectinated, 

 retractile within sheaths. Head with a simple frontal 

 veil. Branchial plumes pinnate, ranged round a dorsal 

 vent, and surrounded by more or less developed tubercular 

 appendages. 



1. T. PENNIGERA, MoutagU. 

 Lin. Trans, vol. xi. p. 17, pi. 4, fig. 5. 



" Body oblong, acuminated almost to a point at the 

 posterior extremity, covered with small spots of bright 

 orange and black on all the upper parts ; the black 

 markings are smallest, and appear radiated under a lens ; 

 the anterior end is sub-bifid, extending at each side into 

 an angular lobe ; tentacula two, subclavated and perfo- 

 liated ; these originate on the upper part, some distance 

 from the anterior end, and each is nearly surrounded by a 

 sort of bipartite wing. The vent is on the back, furnished 

 with five branched appendages, that partly surround it on 

 the fore part, and two large bifid peduncles behind."" 



Length half an inch. 



Milton, Devonshire, at low water (Montagu). 



