NUDIBRANCHIATE MOLLUSCA FEOM THE EASTEEN SEAS. 131 



Branchiae small, consisting of seven small and simple leaflets arranged in a circle, the 

 anterior leaflet somewhat larger than the others, and the posterior pair smallest. Foot 

 long and narrow, slightly tubular, projecting beyond the mantle posteriorly. 



Colour and general appearance. — Mantle opaque white with a slight tinge of yellow, 

 especially on the anterior portion, edged with chrome-yellow, slightly shading off inte- 

 riorly. The whole mantle is covered with minute roundish spots of carmine, irregularly 

 distributed, absent only from the most anterior portion, the spots varying in size from 

 mere specks to roundish definite spots. Tentacles yellowish, but not so bright as the 

 border of the mantle; the bases whitish. Branchiae pale yellow. Foot edged with 

 chrome posteriorly, like the mantle. Under surface yellowish, foot and mantle with a 

 faint edging of chrome-yellow, the carmine spots showing through at the sides of the 

 head. 



Two specimens were found on the under surface of a block of coral in a shoal patch of 

 reef in the midst of the China Sea, named Eiery Cross Reef. It is possible the spot 

 might be uncovered occasionally at low spring tides, but was now 3 feet under water. 

 Notwithstanding this, however, tbese little creatures when captured were continually 

 crawling out of the water and resting upon the dry edge of the vessel in which they were 

 contained, under which circumstances they had a short and stumpy aspect. When placed 

 in the water they were very lively and at once commenced crawling, having first stretched 

 themselves to double their previous length, with a proportionate tenuity. While crawling 

 they had a remarkably slender and linear appearance. They also swam freely on the 

 surface, foot uppermost. (August.) 



In most respects the Chromodoris tenuis agrees with the Doris aspersa, Gould*, save 

 size, his specimen being 1^ inch long by \ an inch broad, and its habitat Vincennes Island, 

 Paumotu group. It may be questionable in this case whether we have specific distinction, 

 or whether size and other slight variation may not be attributable to difference of age, 

 sex, or geographical range. The D. aspersa, D. cerebralis, &c, given by Gould, were 

 drawn from nature by Mr. Joseph P. Couthouy, Naturalist to the U. S. Explor. Exped., 

 I and therefore may be deemed reliably correct. 



• Chromodoris eunerea, Coll., n. sp. (Plate IX. figs. 30-33.) 



Length If inch. Body simple, stout, except when actively in motion, when it becomes 

 I attenuated, obtuse in front. Mantle smooth and entire, having the posterior portion of 

 i the foot exposed during progression, well rounded anteriorly. Dorsal tentacles small, 

 i arising from a small simple sheath, laminated, with scarcely any pedicle. Branchiae 

 composed of seventeen or eighteen leaflets arranged in a convoluted form, the larger 

 i leaflets in front, the smaller behind, leaflet irregularly branched. Head concealed by 

 the mantle and supporting a pair of oral tentacles. 



Colour and general appearance. — Border of mantle narrowly edged with orange; 



general aspect of the upper surface a rich dark brown, with yellowish-white or white 



lines, following the direction of the border of the mantle, but in some places slightly 



ramifying and sometimes anastomosing. The posterior and exposed portion of the foot 



* U. S. Explor. Exped. Mollusca and Shells, p. 304 ; and Atlas, pi. 25. figs. 399 a-c. 



SECOND SERIES. — ZOOLOGY, VOL. II. 18 



