REPORT ON THE REEF-CORALS. al 
neither abundant nor of considerable size. As the different species of Madrepora are 
generally characteristic of the warmer tropical waters, it is probable that the explanation 
of their rarity at, or absence from, Bermuda is to be found in the position of the islands, 
situated as they are at the extreme thermal limit for reef-building corals. 
Besides the species obtained by the Challenger the following forms are also known to 
occur at Bermuda :— 
Oculina valenciennesi, Edw. and H. Isophyllia multilamella, Duch. and Mich. 
Lithophyllia cubensis, Edw. and H. (=Lithophylia  muttila- 
‘3 lacera, Pall. (=Litho- mella, Duch. and Mich.) 
phyllia aegemone, Duch. eA spinosa, Edw. and H. 
and Mich.). Millepora carthaginiensis, Duch. and Mich. 
making a total of twenty-eight True Corals and three Hydrocorals which flourish on the 
reefs. 
2. St. THoMAs. 
Thirteen species of True Corals, representing eight genera, and two species of Hydro- 
corals, were obtained. They include the following :— 
Oculina varicosa, Lesr. Cladocora arbuscula, Lesr. 
» diffusa, Lamk. Madrepora palmata, Lamk. 
3, recta, 0. sp. x cervicornis, Lamk. 
Pectinia profunda, Dana. i prolifera, Lamk. 
Manicina areolata, L. Porites astreoides, Lamk. 
Isophyllia aspera, Duch. and Mich. Millepora alcicornis, L. 
Agaricia fragilis, Dana. »  earthagimensis, Duch. and 
»  frondosa, Duch. and Mich. Mich. 
The coral reefs of St. Thomas are remarkable for the large size and luxuriant growth 
of certain corals upon them, especially two species of the genus Madrepora, Madrepora 
cervicornis, and Madrepora palmata.* 
Three species of Corals are recorded for the first time from this locality. 
Oculina recta, n. sp. | Agaricia fragilis. 
Madrepora cervicornis. 
The complete list of the True Corals now known to occur at St. Thomas includes 
the following seventy-seven species :— 
Oculina varicosa, Lesr. Oculina diffusa, Lamk. 
» pallens, Ehrg. » speciosa, Edw. and H. 
1 Moseley, Notes by a Naturalist on the Challenger, p. 17. 
