UNKNOWN ATLANTIC OR WEST INDIAN PORITES. 108 



91. Porites West Indies x. 26. (-P. Americana incertm sedis sexta et vicesima.) 

 [Lea Mers d'Am6rique, coll. Lamarck; Paris Museum.] 

 Syn. Porites astrmoides Lamarck, Animaux sans Vert^bres, ii. (1816) p. 269, 



Under this heading, Lamarck described (" mon cabinet ") a large slab of encrusting Porites 

 from the American seas, with wavy and gibbou.s surface, and rough margin, and with calicles 

 said to be small, deep, and close together, the calicle walls being " lamelloso-striatia denticulatis." 



There is still one very large astrseoid Porites in the Paris Museum, 30 cm. across the base, 

 and with a label showing it to have belonged to the Lamarck Collection. This may well be 

 the original type. The calicle walls show considerable variations, but are always reticular, 

 the threads being stout ; with very short septa, stout and blunt, but occasionally meeting 

 in pairs. No definite arrangement could be made out as to the details of the columellar 

 skeleton. 



As already noted in the Introduction, where the subject has been discus,sed at length, 

 p. 15, almost every encrusting form of Porites from the West Indies has been " lumped " witli 

 this as all belonging to the same " species." In this volume, we have recognised not only 

 several fundamentally different growth-forms, such as thin and purely creeping, explanate and 

 thickening, and massive, but also the fact that the surface markings show differences referable 

 on a definite principle to their being repetitions of the shape of the early colony. 



De Blainville, in 1834,* mentions Lamarck's coral, calling it " P. astremtes," and refers to 

 some " fig. 3." His own figure shows the surface of a coral raised into large conical mounds, 

 two of them with Balanids opening near their tips. The calicles further show long radial 

 septa, apparently sloping inwards from the wall edges and not very typical of the corals 

 usually regarded as belonging to the astrseoid group. 



Milne-Edwards and Haime, in their Monographie des Poritides,t made the species a 

 synonym of the second of Esper's Madrepora conglomerata (see p. 114 of this volume), but in 

 1860 in vol. iii. of Les Coralliaires, Milne-Edwards described P. astrmoides, quoting the 

 descriptions of Lesueur and Lamarck. The absence of pali is curiously enough not noted, 

 nor the depth of the fossa, and the walls are said to be very thick, coarse, and very echinulate. 

 Indeed, we need not multiply examples of the confusion into which this desire to include all 

 the non-branching Porites of the West Indies into one species has led. What is wanted is a 

 new and correct diagnosis of Lamarck's original specimen and a careful comparison of it with 

 other known so-called " astraeoid " forms. 



In Table III. there will be found a list of such forms already described in this volume from 

 their respective localities. There are three other specimens from unknown localities in the 

 National Collection, and they fall into two kipds, easy to distinguish and to describe. Their 

 descriptions follow on next page. 



* Manuel d'Actinologie, p. 395, pi. bri. figs. 5, 5a. 

 t Ann. Sci. Nat. (3°) xvi. (1851) p. 29. 



