4 THE VOYAGE OF H.M.S. CHALLENGER. 



through it. The polyps are placed on the stem in a uniserial manner ; about 4 mm. 

 apart ; the axis is sUghtly swollen at the places where the polyps are attached ; the 

 tentacles are retractile. On the lower portion of the polyp body the spicules are few in 

 number, but gradually towards the upper portion of the body these are arranged in eight 

 rows, which when the polyp is contracted cover over the oral region and form an 

 imperfect, conical operculum. Numerous specimens of this interesting species were found 

 in the one haul of the dredge off Cadiz. The spicules are the smallest in all the known 

 species. They are either narrow spindles, or of an ol:)long stellate form with a few 

 lenticular-shaped ones on the tentacles. 



Spicule measurements, 0-3-0 -03 ; 0-3-0-025 ; 0-1-0-03 ; 0-075-0-02 mm. 



Habitat. — Station IV., January 16, 1S73; below Cadiz; depth, 600 fathoms; bottom, 

 blue mud. 



4. StropJwgorgia fragilis, n. sp. (PL II. fig. 2 ; PI. Va. fig. 4). 



In this species, which might perhaps be referred to a new genus, the axis seems to 

 have formed a creeping stolon, embedded in the mud ; it is unbranched, very feebly 

 calcareous. The ccenenchyma on the axis is very thin, almost without spicules. 



The polyps are large, elongate, arranged in a single row on the stem ; about 1 to 



5 mm. apart ; the liasal portion of each polyp is narrow, Ijut it gradually widens towards 

 the apex, becoming again slightly contracted about the middle. The polyps measure 

 from 4 mm. to 4"5 mm. in height, with a diameter of from 1 to I'S mm. The tentacles 

 are retractile. 



The spicules on the basal portion of the Ijodies of the polyps are small and scattered 

 all over the surface, towards the middle they become arranged into eight rows, which 

 when the polyps are contracted are continued over the oral cavity, upon the base of the 

 tentacles, forming an imperfect operculum. 



The spicules are of a wavy spindle form, with sometimes one extremity expanded ; at 

 other times, the terminal points are very finely dentate ; a few unsymmetrical double 

 .spindles and minute lenticular forms occur. 



Spicule measurements, 0-68-0-08 ; 076-0-03 ; 0-6-0-04 mm. 



iTo&itoi.— Station 70, June 26, 1873; lat. 38° 25' N., long. 35° 50' W.; depth, 

 1675 fathoms; bottom, Globigerina ooze. 



Subfamily 2. CHRYSOGORGINiE. 



Chrysogoryidee, Veirill, BuU. Mus. Comix Zocil., vol. xi. No. 1, ji. 21, 1883. 



Colony branched. The axis invariably consists of a main stem, springing from a 



calcareous base, which is either disc-hke or stoloniferous, and of branches, which come off 



from the stem in an ascending spiral. The latter are either uniserial {Iridogorgia), or 



