276 MOLLUSCA. 



Length 10 lines ; mouth "sub-inferior, terminal ;" frontal appendages 6, 

 the two central very small ; 3 beautifully plumose branchial filaments, 

 situated at about two-thirds the length of the body from the head ; mantle 

 separated from the disk by a deep channel ; edge of cloak thin and 

 waved ; no eyes apparent ; lateral appendages 9 on each side, terminated 

 by disks. Colour, body white, tail orange, clavate, tips of the processes 

 surrounding the body orange, as are those of the frontal appendages and 

 tentacula ; branchial filaments orange ; on the back are a number of 

 papilla? of this colour, as is likewise a line of spots along each side between 

 the cloak and foot. 



The gliding motion of this beautiful species along the bottom of the 

 vessel in which it was placed for examination was regular and graceful. 



It was cbedged in Strangford Lough, adhering to a Laminaria, by Mr. 

 Hyndman and myself, in January, 1835. Lahinch, Co. Clare. 



Genus Tritonia, Cuvier. 

 T. Hombergi, Cuv., Johnst. Ann. Nat. Hist., vol. i. p. 114, pi. 3, figs. 

 1 and 2, 



A specimen about 4 inches in length, with the examination of which I- 

 have been favoured by Dr. Ball, was found, some years ago, with oysters, 

 at Howth, County Dublin. 

 T. 2)leheia, Johnst. 

 A specimen was taken by dredging in Cork Harbour, August, 1843. — 

 Dr. Ball and Professor Forbes. 



T. lactea, mihi. 



T. of a milk-white colour, with 6 large branchial appendages on each 

 side, bifid and ramosely pinnate ; mantle terminating anteriorly in 4 

 arborescent processes. 



Length of specimen (from spirits) 8 lines ; sheaths of the tentacula 

 deeply fimbriated. Colour milk-white; but with the aid of a lens a few 

 very minute scarlet dots are seen scattered over parts of the body and the 

 branchial appendages. 



The specimen occurred to me when dredging at the entrance of Strang- 

 ford Lough, in the month of October, in company with Mr. Hpidman. 



T. arborescens, Cuv. 

 Several specimens of a small size were taken by Mr. Alder and Dr. 

 Farran at Malahide. Tritoiiui lactea, Ann. Nat. Hist., vol. v. p. 88, pi. 

 2, f. 3, is considered by Mr. Alder a variety of T. arborescens. 



Gemis Melibcea. 

 31. fragilis, Forbes. 

 Three examples of this species were taken on Antcnnularia antennina, 

 dredged in Clew Bay (Co. Mayo) by Dr. Ball, Prof. Forbes, and Mr. 

 Hyndman. 



31. coronata, Johnst. 



Obtained at Glandore Bay, County Cork, in August, 1842, by Prof. 

 Allman, and subsequently in Dublin Bay by Mr. Alder, Avho is now of 

 opinion that the 3IeUb. ornata, Ann. Nat. Hist., vol. ix. p. 33, is a variety 

 of 3[. coronata. 



In Sept., 1851, this species was dredged in 35 fathoms, off the Copeland 

 Islands, by Mr. Hyndman. Its spawn was got at the same time, adhering 

 to Sertulariti abietina. 



