864 " THETIS " SCIENTIFIC RESULTS. 



AGLAOPHENIA CRUCIALIS, Lamouroux. 

 (Plate Ixxxvi., fig. 1.) 



Aglaophenia crucialis, Lamouroux, Hist, polyp, corral, flexibles, 

 1816, p. 169. Id., Kirchenpauer, Abh. Ver. Hamburg, v., 

 1872, p. 26 (but not pi. i., fig. 8). Id., Bale, Cat. Austr. 

 Hydroid Zoophytes, 1884, p. 168 (but not pi. xviii., fig. 8). 

 Id., Billard,(l) Compte Rendu Acad. Sci., cxlviil., 1909, 

 p. 1063. LI, Billard,(2) Ann. Sci. Nat., Zool. (9), ix., 1909, 

 p. 331. 



Anisocalyx crucialis, Costa, Fauna del regno di Napoli. Zoofiti 

 Napoli, 1838, p. 19. 



Vlumularia crihcialis, Blainville, Man. d'actinol. ou de zoophytoL, 

 1834, p. 478. 



Aglaophenia macrocarpa, Bale, Proc. Linn. Soc. N. S. Wales (2), 

 iii., 1888, p. 791, pi. xxi., ligs. 3, 4. 



(Not Thecocarpus crucialis, Billard, Ann. Sci. Nat., Zool. (9), v., 

 1907, p. 328, fig. 3). 



Stations 44, 47, 48, and 55. 



Tropliosome. — Tlie general habit of this species being little 

 known, owing to the deficient descriptions of earlier writers, the 

 fragmentary nature of Bale's (1888) specimens, and the young 

 state of the colony, a pencil drawing of which, by Lamouroux, 

 has been recently described by Billard, 1909(2), I give a descrip- 

 tion of a fine colony collected by the "Thetis." This colony, 

 which is 24 cm. high, consists of a main stem, 4 mm. in diameter 

 at the base, expanding downwards into a contorted root-mass, 

 3 cm. long. The lower portion of the stem is destitute of hydro- 

 clades and is covered by extraneous growths, but at 7 cm. from 

 the base of the stem branching begins. The primary branches 

 are set in opposite pairs on the anterior of tlie stem from which 

 they project almost at right angles. Each lateral series lies by 

 itself in a single plane ; but this is not the case with the two 

 series, for the tips of the branches are always inclined towards 

 the anterior, although in such a way that the planes containing 

 the respective series meet at a wide angle. There are seven 

 pairs of primary branches, the largest of which has a diameter 

 at the base of 1 mm. and a length of 82 mm. Such a branch 

 may bear secondary branches up to 47 mm. long, and this again, 

 branches of third degree, 17 mm. long. The distance between 

 primary pairs of branches varies from 15 to 24 mm., that between 

 secondary pairs is about 15 mm. Remarkably fine as this colony 

 is, its size could have been nothing to that of one represented by 



