SPH^RODORUM. 20/ 



narrowed into a short cylindrical tail, consisting of twelve very nar- 

 row rings, and with the anus on its rounded end. It has much the 

 appearance of a part that has been lost and reproduced. 



I have seen only one specimen, which I owe to the kind attention 

 of Mr. Jenner. It is hard to say which is the anterior and which 

 the posterior extremity, for the proboscis is retracted and invisible. 

 The skin is furnished with very minute spinules, arranged in about 

 four series around each ring ; but it is difficult to see them except 

 when the skin has been raised from the subjacent textures by the 

 maceration; nor could I satisfy myself as to their constancy or 

 nature. 



The position of this worm is very disputable. Were it not for a 

 proboscis, I should not hesitate to have placed the genus in the 

 family LumbricidEe. 



Obs. The two specimens I have seen were dredged in the Firth of 

 Forth. In spirits they are of a uniform wood-brown colour, and 

 closely resemble an earthworm of like size. 



{a) Firth of Forth, Mr, Jenner and Lieut. Thomas, R.N. 



27. SPKffiRODORUM. 



Sphaerodorum, Oersted, Annul. Dan. Consp. 42 (1843). 



Bebryce, Johnston in W. Thompson's Rep. Brit. Assoc. 1843, 273. 



PoUicita, Johnston in Ann. Sf Mag. Nat. Hist. xvi. 4 (1845). 



Char. Body serpentiform : head rather indistinct, conoid, with 

 short papillae on the margin; eyes four: mouth inferior, with a 

 large proboscis, naked at the orifice : segments numerous, similar ; 

 branchiae in the form of a globular papillate tubercle over each foot, 

 which is uniramous, furnished with simple spinets only : anal seg- 

 ment with a mammillary tubercle on each side. 



I first conferred the name of Bebryce upon this genus, but find- 

 ing that this had been previously used by Philippi, I was under the 

 necessity of renaming my worm. The genus is nearly related to, 

 if not identical with, Ephesia of Rathke. 



The relations of this genus are rather obscure. To Nephthys and 

 Glycera it may be considered to approximate in the rudimentary 

 state of the antennae ; but in all other respects there is too great a 

 dissimilarity to allow us to consider them as very nearly affined. 

 The branchial tubercles over the feet might suggest a comparison 

 with Phyllodoce, but there is no structural resemblance ; the lamellae 

 in Phyllodoce being merely modifications of the superior cirrus, 

 moveable and jointed at the base, and acting as a kind of oar in the 

 animal's locomotion ; while in PoUicita they are branchial only, 

 being immoveable, and of no use or applicability as locomotive 

 organs. The difference in internal structure is equally great, for in 

 one genus the organs are veined with ramifications of the blood-ves- 

 sels, while in this, the other, the structure is very distinctly areolar : 



