56 mai)i;hi'()i;ai;ia. 



This specimen, ju(lj,'inp; from the (leseriplimi and ligurc, is not one of tlie massive " Pontes 

 astraoid.es " of tlic West Indies. It is represented as a small, irregulaily disk-like patch, witii 

 slightly crumpled surface, and appears to helong to one of the most primitive forms, viz. a 

 small encrusting disk, see Table III. p. 130. It shows some re.semblance to a form encrusting 

 a large Mussa, iuul described below among the Porites from unknown localities (./■. 9) ; see 

 p. 117. 



Its long echinulate septa, with only faint traces of the palic formula, might belong either 

 to a West Intlian or to an Indo-Pacific form. 



39. Porites St. Thomas 1. {P. Sancti-Thuma: priina.) 



[St. Thomas and Tortola, coll. Duchassaing ; ? Turin Museum.J 



Syn. Porites ralida Duch. and Mich., Mem. surles Cor. des Antilles, Suppl. (1864) p. 94, pi. x. fig. 13. 



Description. — The corallum forms single, stout, raised stems, 20 to 30 cm. high and 3 to 4 

 and more cm. thick, with swollen, slightly flattened tips which fork at wide angles. The 

 living layer seems to cover the whole stem from top to bast;. 



The calicles are sunk, 1 • 5 mm. in diameter, with tliin denticulate walls, and smooth 

 septa, witli 3 to 4 sharp, smooth, cylindrical pali. There is no columella. 



This brief description is taken from the original text. But above, on p. 44, under the 

 heading Porites Guadalupe 4, we have described a very different coral preserved in the Paris 

 Museum, which was also named Porites valida, apparently by Duchassaing himself A 

 comparison of the descriptions and tigures shows that they differ greatly, both in growth 

 (cf PI. XI. fig. 5) and in the characters of the calicles. Porites Guadalupe 4 'liis a surface 

 remarkable for the erect trabeculte standing up like coarse bristles. There is no mention of 

 this character — and it is too remarkable to have escaped notice — in the text of the author's 

 memoire written in conjunction with Michelotti. I do not see on what grounds the two can 

 be united under one name. 



There appears to be a slight discrepancy between the author's original figure and his text. 

 The measurements of the stems given in the latter are 3 to 4 and more cm. thick and 20 to 30 

 cm. (" 8-12 pollicaris ") high. The figure, said to be of natural size, .shows a specimen about 

 2 cm. thick and about 6 cm. high. 



The mistake is due to the addition of the words "Grandeur nuturelle," for, that the 

 specimen was really large, we may gather from the name " valida." 



This Porites is quite unique so far as the records go, quite as unique as are those 

 described and figured by Lesueur {P. Nevis Island and P. St. Bartholomeio 1). The lumping of 

 them all into one or two species is simply the negation of classification. 



