1880.] NATURAL SCIENCES OF PHILADELPHIA. 113 



only in the armature of the tongue, which in the Oolgce exhibits 

 only a single series of (false) rhachidian plates and (on each 

 side) two lateral plates in form approaching those of Polycei-a. 

 The nature of the prostate is unknown ; the armature of the 

 penis not differing much from that ordinary in the large group of 

 the PohjceratidcB. 



Although somewhat approaching to the Euplocami in the form 

 of the appendices of the back, in the armature of the true mouth 

 and of tlie pleura of the tongue, the Triophce still cntirel}^ differ 

 in the form of the tentacles, in the number of the branchial 

 leaves and very likely in the nature of the prostate. 



The Trioph(E have hitherto been only found in the Pacific 

 Ocean. 



1. Tr. modesta, Bgh. n. sp. Oc. Pacificum. 



2. Tr. Carpenteri, Stearns. Proc. of the Cal. Acad, of Sci., April 7, 1873, 



p. 2, fig. 2. Oc . Pacificum (California). 



Tr. modesta, Bgh. n. sp. PI. XIV. fig. 17-20; PI. XV, fig. 1-10. 

 f Triopa Carpenteri, Stearns. L c. p. 2, fig. 2, 



Color e flavido albescens. Appendices dorsales paucpe ; folia 

 branchialia 5. 



Hah. Oc. Pacif. septentr. 



Of this form Dall has obtained a single individual at Yukon 

 Harbor (Shumagins), in August, 1874, at a depth of six to 

 twenty fathoms, on a bottom of sand and stones. The color of 

 the living animal was, according to Dall, " yellowish-white." 



The animal preserved in spirits was of whitish color ; the 

 dorsal appendices, the gill and the rhinophoria more yellowish. 

 The length of the animal 16.0 mm., b}^ a height of 7.0 and a 



Dorsum papilligerum, prsesertim margo frontalis et dorsalis. Branchia 

 pauci (4-5 I foliata, 



Mandibulse triangulares, fortes. Radula fere ut in Polyceratis, dentibus 

 lateralibus (3) et externis (7), sed prseterea dentibus medianis (spuriis) 

 instinicta. 



Mei-ely one species of the genus is yet known, one of the first described 

 Nudibranchiata, the Doris lacera of Abildgaard (Zool. Dan., IV, 1806, 

 p. 23, Tab. CXXXVIII, fig. 3, 4), which has been found too on the coast 

 of America (Cf. Verrill, notice of recent addit. to the Mar. Fauna of 

 North Am., XXXVIII. Amer. Jour, of Sc. and Arts, XVI, 1878, p. 211). 



