_Hab._ San Diego, _Cooper_. From shell washings. The only specimen seen of this tiny species is not quite mature, and has formed no labral teeth. Genus TROPHON, Montfort. _Trophon triangulatus_, Cpr. n. s. State Collection, No. 580, _a_. T. t. parvâ, tenui, albâ, postice latâ, antice attenuatâ; anfr. nucl. ii. minutis, lævibus, attenuatis, vertice declivi, celato; norm. (t. adolescente) iv. subtriangulatis, postice tabulatis, axi fere rectangulatis; suturis acute impressis; antice rapidissime angustatis, canali longâ, arcuatâ; varicibus circ. vii. laminalis, acutis, ad angulum in spinam apertam compressis, spinis radiantibus, parum superne arcuatis; lineâ seu angulo obsoleto peripheriali, suturam continuante; aperturâ pyriformi; labro antice haud indentato. Long. 0·35, long. spir. 0·15, lat. 0·15, div. 70°. _Hab._ Catalina Island, 60 fm.; 4 alive, of equal size, _Cooper_. Resembles the young of _Murex centrifuga_, Hds., and is related to _Trophon muricatus_, Hds. Besides the above species, which were entirely new to science, the fresh and perfect specimens collected by Dr. Cooper, on the Survey, from authentic localities have enabled me to make out and complete the diagnoses of many species first found indeed by other naturalists, but in such poor condition, or with such uncertainty of habitat, that it would have been unsafe to have ventured on their description. [16] From the Greek, for _twisted tooth_. [17] From the Greek for _a sawyer_; from the serration of the teeth, which is unique in the family. [18] From the Greek for _rough skin_. [19] A small island in the British Channel. [20] From the Greek for _chamber on both sides_. REGULAR MEETING, SEPTEMBER 18TH, 1865. President in the chair. Seven members present. Mr. P. M. Randall was elected a resident member. Donation to the Cabinet: Specimen of _Aplodontia leporina_, shot near Lake Tahoe, by Mr. J. M. M’Donald. REGULAR MEETING, OCTOBER 2D, 1865. Mr. Fisk in the chair. Seven members present.