MONOGRAPH OF THE EXISTING CRINOIDS. 649 



MELAKELLA, SP. 



Host. — Stenometra diadenia; on the cirri. 



Locality. — Southern Japan. 



Depth. — Stenometra diadenia occurs in from 80 to 170 fathoms of water. 



>rELANELI.A, SP. 



Host. — Rhizocrinus verrilli; on the calyx. 



Locality. — Off Nova Scotia. 



Depth.— 21^ fathoms. 



Remarks. — In bulk the parasite is actually larger than the calyx of the crinoid. 

 There are two perforations in the calyx on the side opposite that on which the 

 gasteropod is attached, but probably made by the same individual. 



JtELANEIXA, SP. 



On a specimen of Coccometra hagenii in the collection of the Museum of Com- 

 parative Zoolog}' from the Pourtales Plateau, in 200 to 22.5 fathoms, I found an 

 unusually large parasitic Melanella attached to the interradial portion of the disk 

 between the arm bases. Another specimen from the same locality showed a large 

 hole in the same position, apparently made by the same, or a similar, Melanella. 



PARASITIC OASTEIiOPOD. 



Speaking of the small parasitic gasteropods which he found on comatulids at 

 Torres Strait, Lieutenant Potts says that while one or two were colorless, one 

 individual, which occurred upon a very handsome crinoid striped red-brown and 

 yellow, was very similar in color to its host. The shell was perfectly transparent, 

 but the body was red-brown with distinct yellow spots. 



EGO CAPSULES OF A GASTEROPOD. 



Mortensen has reported having found the egg capsules of a gasteropod on the 

 cirri of Hathrometra prolixa. 



PELECVPODA. 



The young of bivalves are sometimes to be found attached to the cirri and 

 columns of the pentacrinites, much more rarely to the cirri of the comatulids, by 

 their byssus. Such association is nothing more than casual, though it is to be 

 observed almost every time that pentacrinites are brought up in the dredge. 



P. H. Carpenter records finding a small Avietda attached to one of the cirri 

 of a specimen of Metacrinus interruptiui from lat. 10° 14' N., long. 123° 54' E., 

 in 95 fathoms. 



POLYZOA. 



Several polyzoans are of casual occurrence on the crinoids, and a number of 

 species of the family Loxosomatidse appear to be not at all uncommon as com- 

 mensals on the cirri of comatulids, especially in the East Indian region. 



