28 MADRACIS AS PERU LA. 



JSfatureUes, but, there arc no sufHoieut grounds for separating them 

 specifically. 



The color is variahle. soinetinies light brown with black or dark 

 brown calicles, or purplish pink of different shades, with or without 

 darker calicles. 



West (jf'Tortufias, in 30 fathoms. 



Saint Nicholas Channel, oH'Bahia (le Cadiz, in 120 fathoms. 



Madracis dccnr/is Verrill [Astro'a dccac/is Lyman, Proc. Bost. Soc. 

 Nat. Hist., Vol. VI., 1857), Plate VIL, figs. 1, 2, and 3, is found to a 

 depth of 17 fathoms. It is generally thin and incrusting, but also rising 

 in club-like masses. A specimen received from Mr. R. Arango, in 

 Havana, forms thick branches bluntly expanded at the end, G cm. 

 high, and 4 cm. in diameter.* S////i>/di'>ra incrmtum Duch. & Mich. 

 I strongly suspect to be a young lladrack decadis, f and BcKmu lamel- 

 losa Duch. & Mich., the full-grown form. | 



Stf/Iophora mirabiUs Duch. & Mich, is a Madracis also, with mas- 

 sive caanenchyma. 



The Museum of Comparative Zoology has also received from Mr. 

 Arango, in Havana, specimens of a coral, which agrees w'ith the 

 description of AxohcUa mi/rimicr, M.-Edw. & H. It differs from 

 Madracis mlrubilk chiefly l)y its striated ca^nenchyma and larger 

 calicles, which, instead of being prominent, are rather sunk btdow 

 the surface. 



* The polyp is piirjilish brown, tcnta<'U's tippeil with whiti- ; ilisk emeralil ijrfcn, moiitli yellow. 

 The mural lines separatin-j (lie |)olyps are tipped with wliite. The tentacles are in one circle, five 

 of them lar^e, prominent, and almost spherical when fnlly expanded, the white tip swellinj; up in 

 that shape. The other tentacles are in <;ronps of three between the larger ones, the total number 

 being thus twenty, or double the number of the septa. There are thus five primary, five secondary, 

 and ten tertiary tentacles. The disk, when fully expanded, projects in the shape of a cone, with 

 the mouth at the apex. The water is kept in a whirling motion over the mouth by ciliary action. 

 The animal bears handling and taking out of the water very well, expanding again after a few min- 

 utes of rest. 



t Duchassaing et Michelotti, Supplement an ^Fcmoire sur les Coralliaires, Plate IX., fig. .■), is evi- 

 dently a magnified portion of .S/i/lnsIrr e/r-//(ins, representeil on fig. 4. Fig. 2 may be intended to 

 represent Sli/lnplinm l)i(:nislaii.<, the numbers having been misplaced. 



t There is again here (Duchassaing et Michelotti, Memoire sur les Coralliaires des Antilles) a 

 confusion in tlie numbering of the figures, and in the figiirrs themselves. One of the generic char- 

 acters of Reussia (differing in no way from those of Madracis) cons'sts in having always ten septa. 

 Fig. 9 of Plate IX., pur[)oi-iing to be a magnifieil portion of lieu.isla lamellom, shows from Ibiirtcen 

 to twenty-seven ! Fig. 8 agrees well with the large specimens of Madracis decaclis from Havana. 



