92 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



Apentamera lepra, new species 

 Plate 13, Figs. 1-10 



Diagnosis. — As for the genus. Color white, mottled with reddish 

 brown. 



Type. — Holotype, AHF no. 25. 



Type locality. — Station 557-36, off White Rock, Isla Partida, Gulf 

 of Calif., in 45 fms., March 8, 1936. 



Distribution. — Gulf of Calif, to Panama. 



Depth. — From 30-50 fms. 



Specimens examined. — The following material from the Hancock 

 Expeditions : 



557-36. Isla Partida, Gulf of California, 45 fms., type and 2 paratypes. 

 863-38. Bahia Honda, Panama, off North Island, 30-50 fms., March 

 1, 1938, 3 specimens (M.C.Z.). 



Remarks. — The type specimens measure 3.5, 3.4, and 2.0 cm. in 

 length ; the gonads are well developed in the 3 individuals, so presumably 

 the animals are full grown. The material has been carefully compared 

 with the other forms with 4-holed knobbed buttons, but it seems impos- 

 sible that it represents the juvenile stages of any of these. The only form 

 which possibly could be considered is Neothyone gibbosa (see p. 113), 

 but the latter has numerous interambulacral feet when it is as large as 

 A. lepra, and its spicules are definitely larger; the buttons are more ob- 

 long and it has numerous rosettes in the tentacles. 



Genus 5. LEPTOPENTACTA H. L. Clark, 1938 



Synonym. — Ocnus Auctores. Nee Ocnus Forbes, 1841. See H. L. Clark, 

 1938, p. 453. 



Diagnosis. — Body slender, skin rigid. Tentacles 10 (or 8), the ven- 

 tral ones small (or lacking). Feet restricted to the ambulacra, rigid, filled 

 with spicules, arranged either in single rows with feet well spaced or in 

 more crowded or zigzaggy rows. Toward the oral and anal ends the feet 

 are scattered and papilliform, often forming 5 valves as in Pentacta. Cal- 

 careous ring simple, or with short posterior prolongations. Retractors 

 short, longitudinal musculature feebly developed. Gonads with few tubes 

 in each tuft, attached near the middle of the animal. 



Spicules reticulated bodies or baskets, larger or smaller, reticulated 

 scales or grains and 4-holed buttons, swollen or knobbed. Feet with or 

 without end plate, with or without supporting rods. Tentacles with large 

 perforated rods or plates ; sometimes also rosettes and smaller rods. 



