1 12 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



2. Neothyone panamensis (Ludwig) 

 Plate 21, Figs. 1-6 



Thy one panamensis Ludwig, 1887, p. 22. — Deichmann, 1936, p. 64 

 (passim) ; 1938, p. 378 (passim). 



Diagnosis. — Medium-sized form with numerous cylindrical tube feet 

 on the ventrum, fewer and most papilliform on the dorsum. Calcareous 

 ring with relatively broad radials with short posterior prolongations, 

 often inward curved, so that they are easily overlooked. Other anatomical 

 features as in the other species. 



Spicules an external layer of baskets derived from oval smooth but- 

 tons, which on their external side develop a number of delicate projections 

 that unite into a fragile meshwork. Spicules in the inner layer small regu- 

 lar 4-holed buttons, strongly knobbed. Ventral feet with large end plate 

 and numerous large, almost flat, smooth supporting plates or rods, ob- 

 viously derived from supporting tables but with no trace of spire. In the 

 dorsal appendages the end plate is smaller, and the supporting tables often 

 show traces of a spire and are more curved. Introvert with delicate but- 

 tons with various projections on the external side; tentacles normally with 

 heavy rods or plates with numerous small holes and in the finer branches 

 smaller, more delicate rods and plates. Apparently no rosettes. Color of 

 dorsum and tentacles black; ventral side mostly white except near the 

 oral and anal ends. 



Type. — Possibly in Italy. 



Type locality. — Coast of one of the islands in the Gulf of Panama. 



Distribution. — Ranging from Panama to Peru, often taken in num- 

 bers with Neothyone gibber. 



Depth. — From tidemark to few fms. depth. 



Specimens examined. — The following individuals secured by the 

 Velero Expeditions : 



391-35. Lobos de Afuera Island, Peru, shore of main island with light- 

 house, rocks, January 17, 1935, 2 specimens. 

 540-36. Puerto Refugio, Angel de la Guardia, Gulf of Calif., shore, 



March 3, 1936, 1 specimen. 

 844-38. Lobos de Afuera Island, Peru, shore, February 14, 1938, 13 

 specimens. 



Remarks. — The type measured only 23 mm., while the present mate- 

 rial (which is well expanded) measures up to 6 cm. in length. It is with 

 some doubt that the material is referred to Ludwig's species, as he main- 



