ANTHOMEDUS.E HYBOCODON. 43 



The hydrocaulus is very thick and massive, about 50 mm. long and unbranched save for 

 the presence of" its roots and stolons. It is covered with a stiff layer of chitin, which is not 

 expanded at the base of the polypite. Polypite large, with 17 to 20 proximal tentacles, each 

 about 6 mm. long. There are also about 27 oral tentacles arranged in several rows. Above 

 the bases of the proximal tentacles there are 8 long, thick, medusa-bearing stolons, which 

 are thickly covered with numerous clusters of medusa-buds. Each medusa-bud has a single 

 very large tentacle. The stem of the hydroid is rusty yellow and the polypite light rose-color. 

 Found at Calbuco, Chile, South America. 



This Hybocodon is closely related to, or possibly identical with, the form from Norway 

 described by Bonnevie under the name Hybocodon prolifer, but it differs from H. prolifer 

 Agassiz in having large, specialized, medusa-bearing stolons. Hartlaub proposes to call this 

 Norwegian hydroid Hybocodon christincc. 



Fewkes, 1889 (Bull. Essex Inst., and also Amer. Naturalist, vol. 32, p. 597), gives a 

 brief description of a medusa from the coast of California which he calls by two names, Steen- 

 strupia occidentahs and S. californica; and which may be derived from Hybocodon chilensis. 

 This medusa is described as follows: Size (?) Bell ovoid without an apical prominence. 

 4 (?) 5 ( ?) rows of meridional lasso-cells extend upward from the 4 tentacle-bulbs, over the 

 exumbrella toward the bell-apex. I long tentacle and 3 rudimentary tentacle-bulbs at the 

 bases of the 4 radial-canals. The long tentacle is ringed at regular intervals and has a 

 large pigmented basal bulb from which there arise numerous medusa-buds. Color ( ?) 

 Velum well developed. 4 straight, narrow radial-canals. Manubrium shorter than the 

 depth of the bell-cavity. No axial canal. Coast of California, United States. 



Hartlaub proposes to call this medusa Hybocodon occidentalis. I find nothing in Fewkes's 

 description to distinguish it from H. prolifer L. Agassiz, but apparently there is less difference 

 between the medusas of the various forms of Hybocodon than between their hydroids. 



Hybocodon christinae Hartlaub. 



Tubular ia prolifer^ Hybocodon prolifer, BONNEVIE, 1899, The Norwegian North Atlantic Eipedition, 1876-79,70!. z6, Hydroida, 



p. z8, plate I, fig. 6. 

 Hybocodon chrislin,t, HARTLAUB, 1905, Zoolog. Jahrbuchern, Suppl. 6, p. 546; 1907, Nordisches Plankton, Nr. iz, p. loz, fig. 98. 



The medusa attributed by Bonnevie to this hydroid has a single well-developed tentacle 

 with a basal cluster of large medusa-buds, each bud bearing a single tentacle. The medusa- 

 buds resemble H. prolifer, but the hydroid is distinguished by bearing its medusae upon 8 

 branched peduncles. 



Hydrocaulus unramified, tubular, springing from a ramified hydrorhiza; occurrence 

 solitary; longitudinal striping, no collar; height about 50 mm. The hydranth has 14 proxi- 

 mal tentacles and 2 distinct circles of (oral) distal tentacles. The oral tentacles are shorter 

 and more numerous than the proximal. There are 8 blastostyles in a circle about midway 

 between the oral and basal tentacles, and these bear numerous medusae upon short pedicels. 

 The medusa-buds have 4 very wide radial-canals, and I highly developed tentacle which 

 exhibits at its swollen base the bud-rudiments of 4 new medusae even before the first has 

 become detached. This species is distinguished by its well-developed, branched, medusa- 

 bearing stolons. Found off Bodo, Norway. It is closely related to H. chilensis Hartlaub, of 

 the northern coast of Chile. 



The medusa-buds in H. christinie appear to be confined to the under side and the sides 

 of the base of the well-developed tentacle. 



Hartlaub, 1907, finds that the medusa becomes 4 mm. high and 3 mm. wide, with thin 

 bell-walls and an evenly rounded apex. The 4 radial-canals and ring-canal are band-like, 

 and wider than in other species of Hybocodon. 



Hybocodon pulcher Hartlaub. 



Auliscus pulcher, SAMUNDSSON, 1899, Vid. Meddcl. Nat. For. Kjobenhavn, Ser. 6, Aarg. i, p. 4Z5, taf. 4, 7 figs. 



Hybocodon pulcher, HARTLAUB, 1905, Zool. Jahrbuchern, Suppl. 6, p. 545 ; 1907, Nordisches Plankton, Nr. iz, p. 96, figs. 9Z, 93. 



Hydroid 40 to 50 mm. high with an oral circlet of 30 short tentacles, and another circlet 

 of 24 to 30 long tentacles around widest part of body of the hydranth. The only distinctive 

 characters of this species are the well-developed medusa-bearing stolons, the symmetrical 



