NTJDIBEANCHIATE MOLLUSCA EEOM THE EASTEEN SEAS. 127 



Of this remarkable species I found one specimen upon a coral block in a shallow patch 

 about 3 feet deep on the Fiery Cross Reef, China Sea, August 4th. The animal crawled 

 freely, but did not float on its back while under observation. When turned over on its 

 back it at once regained its natural position. The posterior portion of the mantle varied 

 in form from various spontaneous degrees of constriction ; sometimes it appeared to be 

 nearly of an oval form, at others it resembled a Tetlujs in shape. 



Subsequently I obtained a specimen of this species on the island of Barundum west 

 coast of Borneo, of a gigantic size for Nudibranchiata, October 8th, upon coral blocks 

 between tide-marks. Of the two specimens found here, one was 6* inches Ion- and ^ 

 wide. In all respects they resembled the one figured, even, to a great extent, in the 

 arrangement of the tubercles or bosses. 



From a careful comparison of the description given by Kelaart* of his Boris exanthemata 

 with my drawings and descriptions of this species, I have come to the conclusion that 

 they are not identical, although evidently nearly allied. The form of the dorsal tentacles 

 the crescentic arrangement of the anterior tubercles, as well as several points in the 

 colour, to say nothing of the constriction of the mantle posteriorly (which might be 

 accidental), all point to different species; nor is the foot of the present species deeply 

 grooved and notched in front, as is the species described by Kelaart. I have named my 

 species from the crescentic arrangement of the tubercles on the anterior border of the 

 notseuni. 



I am by no means certain, though, that the animal named Boris cerebralis, Gould f 

 may not be identical. The Nudibranch referred to, 5 inches long by 2f broad is stated 

 to have been taken from a reef in Sandalwood Bay, Feejee Islands. Comparing 

 Br. Couthouy's coloured sketch with my own, the two not being drawn exactly in a 

 similar position, considerable difference is manifest ; but if taken along with Dr Gould's 

 description in the text, it seems quite possible they may be the same species. Should 

 further research prove this to be the case, B. crescentica must necessarily be regarded as 

 a synonym. 



Genus Chromodoeis, Alder & Hancock (1855). 

 Cheomodoris iris, Coll., n. sp. (Plate IX. figs. 9-11.) 



Length 2J; inches. Body elongated, slightly tuberculated in profile, presenting two 

 rounded elevations, with depression between. Mantle scanty, disclosing the foot on either 

 side and posteriorly ; much waved at the margin. Anteriorly there is a thin-lobed fim- 

 briated veil, and posteriorly it is also divided into three lobes immediately behind the 

 branchial tufts. Borsal tentacles slender, conical, and finely lamellated, situated upon 

 slight elevations of the mantle. Bronchia composed of eight or ten simple leaflets 

 arranged in a cup-shaped form like the petals of a flower ; the leaflets delicately pinnate 

 Foot large, projecting about f inch behind the mantle, and tapering to a point posteriorly. 



* Ann. & Mag. Nat. Hist, 3rd ser. vol. iii. p. 300 (1859). 



t U.S. Exploring Expedition, Mollusca and Shells, Text, 1852, p. 208, and Atlas, 1856, pi. xxiii. figs 393 a-e 

 and Abraham, P. Z. S. 1877, p. 212. ' 



