PROTULA. 267 



SO far as I am able to judge, with Mr. Berkeley's. Indeed, it seems 

 to me, that this very acute and excellent naturalist has confounded 

 the S. tubularia of Montagu with the S. vermiculcms of authors ; 

 for, on this supposition, his remarks on their distinctive characters 

 will be found perfectly correct and decisive. 



(a) Berwick Bay, Dr. Johnston. 



(b) Torbay, J. R. Griffiths. 



(c) Loch Jarriden, R. M'Aridrew. 



2. P.? Dysteri, tubes slender, cylindrical, creeping and wavy, uniting 

 into irregular masses. 



Protula Dysteri, Huxley in Edinb. New Phil. Journ. (1855) i. 118. 

 pi. I. fig. omn. 



Hab. The coralline region. 



Desc. " The vermidom (as one might conveniently term the habi- 

 tations of tubicolar annelids in general) of this annelid is com})osed of 

 very fine, more or less undulated, white, calcareous tubes, attached 

 by one end to some solid body. Rising from this fixed base, they 

 unite together side by side into irregular bundles, and these bundles 

 anastomose like bundles of nerves in their plexuses — lea\ing irregular 

 spaces here and there, and thus forming a kind of coarse sohd net- 

 work. Each tube has a circular section, but can hardly be called 

 cylindrical, because it is thickened at intervals, so as to be obscurely 

 annulated. 



" When placed in a vessel of clear sea-water, the annelids issue 

 from the tubules of their vermidom, and each spreading out its eight 

 branchial filaments and displaying its bright red cephalic extremity, 

 the mass assumes a very beautiful and striking appearance, singu- 

 larly resembling a tubuliparous polyzoarium." 



"Protula Dysteri possesses a very elongated body, which may be 

 conveniently divided into a cephalic, or thoracic, an abdominal, and 

 a caudal portion. The cephalic portion can hardly be said to con- 

 stitute a distinct head, for the oral aperture, which is wide and fun- 

 nel-shaped, is terminal. The dorsal margin of the oral aperture is 

 formed by a prominent rounded lobe, beneath which are two riclily 

 ciliated, short filaments, which adhere to the base of the branchial 

 plumes, and might be regarded either as their lowest pinnules, or 

 perhaps, more properly, as tentacles analogous to the operculigerous 

 tentacles of the Serpiilce. On the ventral side the margin is deeply 

 incised, so that a rounded fissure, bounded by two lips, lies beneath 

 and leads into the oral cavity. From each side of the head springs 

 a distinct branchial plume, whose peduncle immediately divides into 

 four branches. These are beset with a double series of short filiform 

 pinnules, the origins of each series alternating with those of the other. 

 The termination of each branch is somewhat clavate, and when ex- 

 panded, the eight branches are usually gracefully incurved towards 

 one another, the whole having not a little the aspect of a Comatida. 



" The thoracic ])ortion of the body is short, but wide and some- 

 what flattened. It is produced laterally into nine pairs of close-set, 



