MUSEUM OF COMPARATIVE ZOOLOGY. 289 



Faxon, inhabit either fresh water or live inland in moist localities. 

 It is, however, quite remarkable that in none of the other fresh-water 

 lakes in which marine forms have been found, Lakes Superior, Michi- 

 gan, Lake Wetter, or in Lake Baikal, and other lakes supposed 

 formerly to have had a connection with the sea, has this family as 

 yet been discovered, though a closely allied species of Allorchestes 

 has an extensive geographical distribution in the rivers of the North- 

 ern United States. It must also be remembered that we have four 

 species of Orchestias which are land inhabitants, living under damp 

 leaves at a considerable distance from the sea. 



There were a few other interesting specimens found in this locality 

 which unfortunately have been lost. One species of Millepora, very 

 closely allied to M. alcicornis, and a species of a Crustacean, closely 

 allied to a large Aega, which was found in a pool near Tilibiche. 



In the saline pools there were numerous specimens of fresh-water 

 Gastropods (Hydrobinise). Diptera and Neuroptera larvce were found 

 in abundance. 



These corals are fossilized into a compact crystalline limestone, 

 the crystals having generally destroyed the internal structure ; they 

 are impregnated with salt, which effloresces after washing. 



Isophyllia duplicata n. sp. (Plate, figs. 1, 2, 3.) 



Rounded masses about 10 cm. in diameter; the lower surface is not pre- 

 served, so that the absence or presence of an epitheca remains undetermined. 

 Calicles coalescing in very sinuous series, containing sometimes six or seven 

 centres which remain, however, always very distinct. The adjacent walls 

 remain always separated by a furrow, across which the costse are frequently 

 continuous. The latter are thick and appear to have borne blunt spines. 

 The septa are thick, with blunt equal teeth ; four cycles, with occasional 

 rudiments of a fifth, the septa of the first, second, and sometimes third, not 

 very different, and reaching to the centre. No paliform lobes, but sometimes 

 a slight thickening of the septa in their place. Columella generally absent ; 

 occasionally one or two obscure papilla? represent it. Width of calicinar 

 valleys 5 to G mm., of mural furrows 2 to 3 mm. 



This genus and its nearest allies (Symphyllia we do not think can be 

 separated from it) is not represented in any lower strata than the Tertiary, 



