178 



minoribus plus minusve muriculatis intcrpositis ; v. altera; costis fre- 

 quentioribus minoribus squamigeris, costulis muriculatis interpositis ; 

 auriculis (nisi area ad sinum tendente) radiis numerosis spinulosis 

 munitis ; cavositas valvse integrse rubricata ; v. alteras pallidior, fere 

 alba. Long. 3.5 ; alt. 3.75; lat. 1.5 poll. Inhabits Hakodadi Bay, in 

 shelly mud, 10 fath. W. S. 



Resembles generally P. senatorius, but is more elongated, the small 

 ear longer, and the ribs much less regularly disposed. It is still more 

 like P. caurinus G. in which the ribs are angular and more regularly 

 disposed. In old and heavy specimens the scales are worn oft'; and 

 in some young specimens, too, they are inconspicuous. 



Ostrea rivularis. T. discoidea, subcircularis, tenuis ; valva 

 inferior crassior, purpurascens, costis radiantibus remotis, interruptis, 

 subtubulosis munita ; v. superior simplex, rivulis ramosissimis purpur- 

 ascentibus venosa : cavositas minime profunda, ovata, alba cinereo 

 late marginata ; cardine debili. Diam. 60 ; lat. 10 millim. Inhabits 

 the China Seas, as indicated by shells adhering to it. 



The rays of little tubes below, and the veins above, are unusually 

 clear, distinctive characters. 



Plicatula simplex. T. parva, solida, ciner^p, vel rubida, flabelli- 

 formis, symmetrica, quadrantem haud sequans ; marginibus rectis, 

 planulatis ; costis praacipuis 6 et costulis numerosis lateralibus, etiam 

 laminis concentricis numerosis munita. Long. 15 ; lat. 8 millim. 

 Common at Kagosima Bay and Simoda, 5-20 fath. W. S. 



Placunanomia umbonata. T. discoidea, talcosa, fragilis, admo- 

 dum levigata, straminea : valva superior obsolete radiata, et umbonem 

 submarginalem monstrans ; fossa, cardinali minime profunda : v. in- 

 ferioris perforatione acute-ovato ; clavicula vix dilatata, quasi costii 

 secundum marginem perforationis prolongata. Diam. 25 ; lat. 4 mil- 

 lim. Inhabits Kagosima Bay. W. S. 



It most resembles P. claviculata from Mazatlan. 



The preceding descriptions were published in the Proceedings of the Boston 

 Society of Natural History, under the following dates, beginning with — 



Page 101. Succinea lauta ------- Vol. VI. 422. Feb. 1859. 



" 105. " lvrata ------- » VII. 40. June, 1859. 



" 110. Paxillus tantillus ------ " " ]38. Oct. 1859. 



" 115. Patella grata -------- " " 161. Dec. 1859. 



" 120. Terebratula transversa- - - - - " " 323. Sept. 1860. 



" 133. Drilliaeborea- ------- " " 337. Oct. 1860. 



" 137. Mangelia semiassa " " 382. Dec. 1860. 



" 140. Turritella gracillima ----- « « 386. Jan. 1861. 



" 145 Rissoina villica ------- " " 401. Feb. 1861. 



" 153. Tectarius luteus - ------ " VIII. 14. Mar. 1861. 



" 171. Mysia obliqua ------- « « 33. Ap'l, 1861. 



