TUBULARIAD.E : CORYMORPHA. 53 



rate bulbule is of a roundish or oval shape, consisting of a white 

 albuminous coat with a dark red centre. 



Van Beneden has referred this Tubularia to the T. calaraaris of 

 Pallas, from which the size alone is sufficient to prove that it is 

 distinct. I have felt rather uncertain whether to refer our species 

 to Van Beneden's T. calamaris or to the T. coronata of Abildgaard ; 

 but in the latter the polype-tubes are simple or unbranched, while 

 most of our specimens are branched near the base, as they are in 

 T. calamaris of Van Beneden. The real distinction between the spe- 

 cies is this : in T. gracilis the bulbules are shortly pedunculated, 

 while in T. coronata they are supported on a long branched pedicle. 

 Perhaps T. gracilis, Harvey, may be found to belong to the latter. 

 Mr. Harvey says that the tube is " hollow throughout and single ;" 

 but then he describes the bulbules as if they were sessile, — " two or 

 three confused rows of alternate white and red short papillfe." Mr. 

 Harvey found his specimens in a locality where they can easily be re- 

 examined : " at the steam bridge on the river Dart, where it grows 

 in clusters between the links of the chain over which this floating 

 bridge is propelled." And he adds, " I have since observed the 

 same animals growing on the links over which the floating bridge at 

 Devonport runs, and there they do not occupy a space exceeding 

 150 feet." I have observed what is undoubtedly the same species in 

 a similar position at Southampton. 



Of the Tubularia polyceps (Rep. Brit. Assoc. 1834, p. 601 ; and 

 Edin. New Phil. Journ. xxi. p. 93.) Sir J. G. Dalyell has given no 

 description. It is probably the same as our T. gracilis. 



The Tubularia flabelliformis oi Adams in Lin. Trans, v. p. 12, 

 is a minute parasitical alga of the family Diatomacete. 



7. CoiiYMORPHA,'" Sars. 



Character. — Polyp'idom suhcyllndrical^ short, very thin 

 and membranous, rooting in sand and bulged at the base : 

 Polype elongate, naked above and free of the polypidom ; the 

 head clavate, encircled near the base with a series of long 

 filiform tentacula, and around the proboscidiform mouth there 

 is another set of short ones. 



* From xopwn a club, and fiop(pri form. — The generic character of Sars is as fol- 

 lows : " Corpus longum, cyliudricum, molle, superne clavato-vesiculosum, infenie 

 conico-attenuatum, tuhiilo cutaceo hyalino tenuissimo partem corporis inferiorem cir- 

 curadante, libure (non affixum) insidens. Clava conica, basi serie tentaculorum 

 longonmi circumdata, et os tentaciJis brevibus sparsis." 



