108 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



the tip. Feet with large end plate and numerous supporting tables with 

 a conical spire. Introvert with oblong tables, disk with knobbed edge 

 and low spire. Tentacles with rosettes and delicate rods. Color brown, 

 tentacles dark, blackish. 



Type.— M.C.Z. 



Type locality. — Isle Grande, west coast of Mexico (Lat. 170° 46' 

 N.;Long. 101° 42' W.). 



Distribution. — Known from the type locality. 



Depth. — From 7 fms. 



Specimens examined. — The type. 



Remarks. — The type measures about 4 cm. with the tentacles with- 

 drawn. The anterior portion is well preserved, but most of the intestine 

 and respiratory trees are eviscerated. The gonads form well-developed 

 tufts near the middle of the dorsal midline. 



The spicules are extremely characteristic and different from those 

 found in all other species known from the Panamic region as well as the 

 adjacent waters. Superficially they may be mistaken for those of Phylloph- 

 orus aculeatus Ludwig, but comparison of the figures (plate 25) shows 

 that they are entirely different. 



Genus 9. NEOTHYONE, new genus 



Stolus Selenka (partim), 1867, p. 356. 



Diagnosis. — Medium-sized forms with numerous feet; skin thick, 

 packed with spicules. Tentacles 10, the 2 ventral smaller. Calcareous 

 ring with posterior prolongations on the radials, in some species fairly 

 short and soft, often inward curled, so that they easily escape notice. 

 Single stone canal, one or more Polian vesicles, ventrally placed. 



Spicules an external layer of specially modified buttons, with spines 

 either on the outer handle or transformed into reticulated baskets, in 

 some cases lost with advancing age. An inner layer consisting of numerous 

 knobbed buttons, mostly with 4 holes; knobs distinct or almost obliter- 

 ated. Feet with large end plate and numerous supporting tables with or 

 without a spire. Introvert with a varying amount of tables or reduced 

 buttons; tentacles with a varying number of heavy plates or rods, some- 

 times reduced with age. Rosettes seem to be present in certain species, at 

 least in the younger individuals ; possibly they represent a variable char- 

 acter. 



Type species. — Neothyone gibber (Selenka). 



