EASTERN COAST OF THE UNITED STATES. 31 



the description of Dr. Stimpson and the drawings which he has generously placed at my 

 disposal. 



Genus Bicidium Agassiz. 



Bicidium Agassiz, Proceedings of the Boston Society of Natural History, vii. p. 24 (1859). 

 (?) Philomedusa Muller, Arch, fiirg Natur. xxvi. p. 57 (1860). 



Body elongated, turbinate, or obconic, tapering to the base. Column sulcate, surface 

 without apparent suckers or cinclidre, uniform along its whole extent. Tentacles twelve, 

 in two cycles, short, thick, marginal. Mouth large, enclosed at one end by a prominent 

 extension of the disk, forming a large conchula, which is partially divided into tentacle- 

 like lobes at the summit; the other end surrounded by small lobes corresponding in 

 number to the tentacles. Base with a terminal pore. 



This genus is very closely allied to Peachia Gosse, but has a still more remarkable 

 structure surrounding the mouth. It also lacks suckers, and has the tentacular system 

 less developed. 



Bicidium parasiticum Agassiz. 

 Bicidium parasiticum Agassiz, Proceedings of the Boston Society of Natural History, vii. p. 24 (1859). 



Plate I. figures 14, 15. 



Form usually turbinate, tapering below to an obtusely rounded base; in contraction 

 sometimes ovate, largest in the middle, broader than long, each end involved. Surface 

 strongly furrowed by twelve sulcations corresponding to the internal lamellae, between the 

 grooves much swollen and corrugated by transverse wrinkles, no suckers apparent. Tenta- 

 cles twelve, short, thick, swollen in the middle, obtuse at the tips. Conchula or proboscis 

 greatly developed, surrounding one end and about one half the length of the mouth, and 

 when expanded about as long as the tentacles ; its summit is divided into three principal 

 lobes, one opposite the angle of the mouth and one on either side of this, and two subor- 

 dinate ones, which are about opposite the centre of the mouth. The remaining margin of 

 the mouth is divided into prominent lobes, decreasing in size as they approach the angle 

 opposite the conchula. 



Color light purplish brown with a bluish iridescence, similar to that of Ci/anea arctica. 



Length in expansion, 1.25 inches; greatest diameter, .4. (Coll. Mus. Comp. Zool.) 



Nahant, Mass., to Eastport, Me., parasitic on the large red jelly-fish, Cyanca arciica, often 

 imbedded in the tissues of the lower surface of the disk. 



Family Cerianthid^e. 



Cerianlhidce Milne-Edwards and Haime, Distribution methodique (1852) ; Miiae-Edwards, 

 Coralliaires, i. p. 306 (1857). llyanthidce {pars) Gosse, Ann. and Mag. of Nat. Hist., 3d ser. 

 i. p. 417 (1855); Actin. Brit. (1857). 



Form elongated, tapering to the rounded or pointed base, which is destitute of a disk. 

 Tentacles not retractile, greatly developed, numerous, arranged in two series, one marginal 



