Acanthopleura fluxa, Cpr.? n. s.

A. t. “A. scabræ” simili, sed latiore, pallidiore; viridi, rubro-aurantio conspersâ; valvis rectangulatis; suturis marginalibus haud conspicuis; areis diagonalibus satis distinctis; radiis obtusis fluxis ii., alterâ diagonali, alterâ suturali; totâ superficie conspicue granulosâ, granulis acutioribus præsertim albidis; jugo obtuso, vix vallato: laminis insertionis ut in A. scabrâ instructis.

Long. 0·60, lat. 0·40, div. 110°.

Hab. Santa Barbara Island, Cooper.

Foot, in the only dried specimen seen, extremely thin, flat, and narrow.

Genus Ischnochiton, Gray.

Ischnochiton veredentiens, Cpr. n. s. State Collection, No. 518 a (bis).

I. t. parvâ, albidâ, rosaceo tinctâ; valvis gothice arcuatis, jugo subacuto; totâ superficie minute granulosâ; areis lateralibus conspicue definitis, minoribus, costis diagonali et suturali validis instructis, bullis valde expressis munitis; valv. term. costulis subobsoletis radiantibus; areis centralibus clathris longitudinalibus utroque latere circ. viii. distantibus, expressis, subgranulosis, supra jugum obsoletis; interstitiis â costulis subradiantibus decussatis; umbonibus conspicuis; marginibus umbonalibus à costis bulliferis valde indentatis, dentibus viii.-x. jugum versus obsoletis, marginibus haud intortis; mucrone submediano, vix extante; marginibus lobatis eleganter à clathris pectinatis: intus, sinu maximo, planato, interdum serrato; laminis insertionis acutis, late unifissatis, valv. term. circ. viii-fissatis, subgrundis conspicuis; limbo pallii squamis majoribus, planatis, tenuibus, vix striatis.

Long. 0·25, lat. 0·10, div. 90°.

Hab. Catalina Island, 20-30 fm., Cooper.