Chap. V. BOUGAINVILLIA SUPERCILIARIS. 



289 



thickness, bulges unequally, upon one side, near the base. This lateral bulging 

 becomes gradually deejjer, until the bud assumes the form of an urn-shaped body, 

 attached by one of its edges (wood-cut 36), with its summit 

 near the base. The contents of the buds, as they increase ^'a- 36. 



in bulk, become more and more disconnected from the wall, 

 the lip opens, the wall is split laterally, and, with the in- 

 creasing bulk of the contents of the bud, soon dwindles 

 down to a band, passing like a hoop over the contents of 

 the burl, ^vhich, at this period, appear to be a mass of yolk 

 substance in process of segmentation. The wall soon disap- 

 pears altogether, and the yolk substance remains a sphere, f 7-7" ---■ ^^^ 



ojjii>-ic, female medus»-buds in van- 



attached to the peduncle of the bud, fittino- into a sort of °"* ^'"^^^ ""^ development. 



socket formed by the remnant of the outer wall. 



The various shapes of the hydra (PL XXVII. Ftffs. 23, 24, and 25), as illustrated 

 here, are characteristic of the habits of all the Eudendrioids. Fiff. 26 shows very 

 well the broad disk (dc), upon which the proboscis (p) arises, and also exhibits 

 the true character of the tentacles (0- All Hydroids having taper-pointed ten- 

 tacles are able to contract them into a club-shaped form, as we have represented 

 them in some of the figures on this plate {Fiffs. 12, 22, 23, 24, and 25), but 

 none of the truly clavate tentacles, such as those of Pennaria (PI. XV. Fiff. 2, t^), 

 of the reproductive hydra of Hydractinia (PI. XVI. Fiffs. 2% 2\ 3, &c.), of Coryne' 

 (PI. XVII.), and of Halocharis (PI. XX. Fiff. 10), can assume a pointed form. 



On PI. XXVII. this species is represented under the name of Thoa dispar. 

 But I am now satisfied that the name Thoa cannot safely be retained for 

 Eudendrium. 



SECTION III, 



BOUGAINVILLIA SUPERCILIARIS AG. 



Proles h>/droidea. — Th^ hydroid of this species has always been found in the 

 purest sea-water, along the rocky shores of our coast. It grows in clusters, not 

 more than two inches high, and is usually attached to some rock, or to the shell of 

 a Mytilus, and seldom to sea-weeds. The hydrarium (PI. XXVII. Firj. 1), the stem 

 of which is about as thick as a cambric needle, has a deep red tint, and branches 

 rather irregularly, though more or less alternately and spirally, and in like manner 

 do the secondary branches arise from the primary ones. The base of every branch 

 {Fig. 2, a h c d e), as well as every pedicel {Fig. 3, c) of the horny sheath, is 



vo'.. IV. 37 



