46 NOTES ON A COLLECTION OF CALIFORNIAN NUDIBRANCHS. 



lateral smooth with a large base and a large sickle-shaped hook. The liver 

 is trilobed, but is wholly contained within the body cavity, and is not rami- 

 fied. The hermaphrodite gland consists of several separate lobes lying on 

 the front part of the liver. According to MacFarland, the glans penis is 

 armed. 



In some respects, such as the structure of the frontal veil and of the herma- 

 phrodite gland, this animal resembles Scyllaea, and perhaps the knobs on the 

 papillae may represent branchiae. In others, particularly the absence of 

 rhinophore sheaths, it approaches the Aeolit/s, and in general appearance is 

 not unlike Proiionofus. I'ut the undivided liver is remarkable in conjunction 

 with the other characters, and both the position of the anus and the dentition 

 are peculiar. 



The genus will probably be made the type of a new family. At present 

 two species are known : — 



1. Dirona picta, Mac Farland, California, described below. 



2. D. albolimata, Mac Farland, California. Prof. Mac Farland states 

 that this animal is of a beautiful, translucent grey, save for a narrow band 

 of pure white edging the veil, the cerata, and the caudal crest ; also a similar 

 line running down the stalk of each rhinophore and meeting in the median 

 line. Cerata smooth, radula about 32x1.1.1.1.1. 



Dirona picta, M.icKailand. 

 PI. vii, figs. 6 — II. 



The animal which was obtained at Dead Man's Island, San Pedro, 

 measures 19 millim. in length and 7 in breadth : the height to the dorsal 

 surface is 5 millim. and to the tip of the highest papilla 9. The length 

 includes the buccal mass which is everted. The colour is whitish but the 

 greenish viscera can be seen through the integuments, and the back and 

 sides show traces of reddish brown pigment. The living animal is described 

 as having brown sides with rather sparse, small, yellowish spots. From a 

 sketch of the dorsal markings it would appear that yellow predominated in 

 this region and that the brown colour was represented only by a reticulate 

 pattern (figs. 6 and 7). 



The animal is stoutly built. The foot is broad and slightly expanded 

 in front, where it is rounded, without a groove or lateral angles. The back 

 is flat and minutely tuberculate. The margin is not prominent but is 

 marked by a line of papillae of which there are about 15 on each side and 

 one or two over the tail. They are mostly minute but some are as much 

 as 2 millim. high. The line is generally single but double in some places. 

 Besides these papillae there are a number of much larger ones about 4 

 millim. high, many of which have become detached, so that it is difficult to 

 be certain what was the original arnuigement, but it would appear that there 

 were about 5 on each side within the line of smaller papillae, and that the 

 largest of all were at the end of the body. They are deciduous, somewhat 



