REPORT ON PHILIPPINE HYDROIDA 229 



ACANTHELLA EFFUSA (Busk) 

 Plate 45, figs. 1, 2 



Plumularia effusa Busk, Voyage of the Rattlesnake, 1852, vol. 1, p. 400. 

 Plumularia effusa Kirchenpauer, Ueber die Hydroidenfamilie, Plumulari- 



dae, pt. 2, 1876, p. 46, pi. 1, fig. 4. 

 Acanthella effusa Allman, Hydroids of the Challenger, pt. 1, 1883, p. 27, 



pi. 6. 



This remarkable species is represented by several fine specimens 

 in the collection under consideration, and fortunately the gonosome, 

 hitherto unknown, is included. Allman's description is accurate and 

 fairly complete, but the following items may be added : 



Trophosome. — Stem and main branches not fascicled, the lower 

 part of the former not bearing hydrocladia but beset with four regu- 

 lar rows of stubby, thornlike processes which bear nematophores, 

 often in pairs, and are of the usual eleutheroplean type. (Allman 

 represents these as sharp thorns in his figure.) The stem is also 

 divided into regular internodes. The distal branchlets bear thorn- 

 like processes as described by Allman. The hydrocladia are quite 

 dense, divided into regular internodes, each bearing a hydrotheca. 

 Hydrocladial internodes with usually three strong internal thicken- 

 ings back of the hydrotheca. Hydrotheca typically pitcher-shaped 

 as described by Allman. 



Gonosome. — (Hitherto unknown.) Gonangia borne on branches 

 at bases of hydrocladia where they form a double row on one side 

 of the branch. They are small, triangular in outline, shaped like 

 flattened cones. They are not protected by specialized branches in 

 the form of phylactogonia. 



Localities. — Dredging station 5139, vicinity of Jolo, Jolo Light. 

 6° 6' N., 120° 2' 30" E. ; depth, 20 fathoms. Station 5141, vicinity of 

 Jolo, Jolo Light, 6° 9' N., 120° 58' E.; depth, 29 fathoms. Station 

 5146, Sulu Archipelago, vicinity of Sulade Island, 5° 40' 40" 

 N., 120° 48' 50" E. ; depth, 24 fathoms. Station 5149, Sulu Archi- 

 pelago, vicinity of Sirun Island, 5° 33' N., 120° 42' 10" E. : 

 depth, 10 fathoms. Station 5174, vicinity of Jolo, Jolo Light, 6° 3' 

 45" N., 120° 57' E.; depth, 20 fathoms. Station 5484, between 

 Samar and Leyte, vicinity of Surigao Strait, Cabugan Grande 

 Island, 10° 28' N., 125° 20" E.; depth, 76 fathoms. Station 5557, 

 Jolo Island and vicinity, Cabalian Point, 5° 51' 30" N., 121° 1' E. ; 

 depth, 13 fathoms. 



Distribution. — Torres Strait (Busk), Philippines (Kirchenpauer), 

 reefs off Zamboanga (Allman). 



This is one of the most striking species of plumularians that the 

 writer has ever seen, and the graceful, pitcher-shaped hydrothecae 

 are unique in form. So far as I know, this species has not been seen 



