TUBULARIA COUTHOUIF. 403 



clusters of berry like gonopliores, which droop gracefully from aiuong the tentacles, complete the 

 attractions of this beautiful hydroid. 



During the spring and summer months Tuhaluria indivisa is in its greatest perfection, 

 though in some localities it may still be found in good condition until late in the autumn. It is 

 during the season of its most active growth, and when the hydranths with their racemes of gono- 

 phores have attained their greatest size and perfection, that these may be seen to be perpetually 

 cast off and renewed, the stem increasing in height with the formation of each successive hydranth. 

 But towards the end of summer the renewal of the hydranths after the casting off of the old ones 

 appears to cease, and we now usually find the upper parts of the perisarcal tubes empty, while 

 their lower parts and the hydrorhiza are still filled with the living coenosarc. In this state, I 

 believe, they generally remain during the winter, ready on the return of spring to throw out new 

 hydranths, and these hydranths, with their clusters of gonopliores, undergo in their turn successive 

 shedding and renovation, until the autumnal months once more put a check to the activity of 

 their functions. Each successive renovation of the hydranth, and consequent elongation of the 

 stem, is marked by a slightly elevated annular ridge on the surface of the perisarc. 



Tubularia indivisa will continue to live for some time in the confinement of our aquaria, fre- 

 quently throwing off and renewing its hydranths, and giving origin to hundreds of embryos, 

 which during their actinula stage look like minute spiders creeping over the bottom of the tank 

 or floating passively in the water. Many of these actinulae will pass through subsequent phases 

 of their development and attain their fixed condition, in which they may be seen rooted in multi- 

 tudes to the sides of the vessel, a forest of diminutive Tuhularice. They often, also, attach them- 

 selves to the stems of the parent colony, where they will continue to grow as long as these 

 stems may afford them sufficient surface of support. 



The species seems to range from the upper limit of the Laminarian zone to a depth of thirty 

 fathoms, or even more. At extreme low-water spring tides it may frequently be seen growing 

 luxuriantly in the rock pools or spreading over the rocks where these are still washed by the 

 sea. 



It is, perhaps, generally distributed over the European shores of the Atlantic. Some of 

 the finest specimens have been obtained from estuaries where the influence of the fresh water has 

 not yet wholly ceased to modify the saltness of tlie sea. 



Under the name of Tubularia giyaniea, Lamouroux (' Exposition Methodique,' tab. LXVIII, 

 fig. 5) figures the dead stem of a large Tubularia, which he informs us attains a height of from 

 1 2 to 1 5 inches. He gives no description which might aid in its determination, but it is probably 

 only a large form of T. indivim. 



*^* 2. TUBUL.A.UIA CouTHOuir, Agassiz. 



TuBULARLA. CouTHoi'vi, — Affussiz, in Contr. Nat. Hist. U. S., vol. iv, p. 226, pi. xxiii a, figs. 



8, 9, pi. xxiv, pi. xxvi, figs. 1 — 6. Alex. Agassiz, in 

 Illustr. Catal. N. A. Acalcpli.-c, p. 196. 



TROPHOSOME 



— HTDEOCAULrs varvint? in lieiglit from about three inches to six 



