inhabiting the Estuary of the Dee. 201 



dida; and perhaps it is one of the most beautiful of this beau- 

 tiful tribe. It inhabits the Mediterranean Sea, the south coasts 

 of Europe and England, — the Menai Straits being the only 

 northern locality known when the Ray Monograph was published. 

 In July 1851, however, my friends Messrs. Byerley and Price, 

 when on a visit to Hilbre Island, each picked up a specimen of 

 a new species of Antiopa possessing the crest of that genus, but 

 in the tuberculated papillae approaching still more closely to 

 Proctonotus than did the first Antiopa. One of these was sent to 

 Mr. Alder, but died before it reached him ; still, being a unique 

 specimen, it was figured, and appeared in the Monograph under 

 these adverse circumstances. Much as it resembled Proctonotus, 

 the crest was with reason considered sufficient to distinguish it, 

 and it was described under the name of Antiopa hyalina, the 

 original species having in the mean time been renamed A. cris- 

 tata — as I think, unfortunately, since the crest constituted a 

 generic, and not a specific distinction. In August 1854 Mr. 

 Byerley again met with a specimen of Antiopa hyalina within a 

 few yards of the original spot. This was the first Mr. Alder saw 

 alive, and it was a much superior specimen, more mature, and 

 in altogether better condition than that figured, from which it 

 differed in the greater length and more pointed character of the 

 dorsal tentacles, the superior attenuation of the papilla?, and 

 greater length of the tail. A careful drawing of it was made 

 by Mr. Hancock, but too late to replace the one engraved for 

 the Monograph. 



This remarkably local species has hitherto eluded search in 

 every other spot, and is peculiar to Hilbre Island in the Dee ; 

 and there, until the summer of 1859, it was the sole representa- 

 tive of the genus. In July of that year, however, I was so for- 

 tunate as to discover some fine specimens of Antiopa splendida 

 (or cristata). These were such beautiful objects that I sent the 

 largest to Mr. Alder, who informed me that even finer specimens 

 occur in the Mediterranean. I look upon it, however, as the 

 most lovely of the tribe, but one which has met with scant 

 justice in that, for the most part, exquisitely-illustrated work. 

 But it would perhaps be scarcely possible to delineate it satis- 

 factorily : it deserves the name of hyalina even more than its 

 congener. Mr. Moore, who visited Hilbre about a month after 

 I had discovered Antiopa cristata, and who was with me on 

 that occasion, upon looking into the rock-pool in which I had 

 found them, saw an individual of that species, and, with it, one 

 with which he was not familiar. He brought it to Liverpool ; and 

 on examination, it turned out to be another specimen of Antiopa 

 hyalina. Thus this rare Nudibranch has been taken in the 



Ann. fy Mag. N. Hist. Ser. 3. Vol.vi. 14 



