WEST INDIAN ISLANDS PORITES. 45 



25. Porites Guadalupe 5. (/'. Guadcdupensis quinta.) (I'L XVI. fig, 6). 

 [Guadalupe ; Paris Museum.] 



Description. — The corallum rises as a stout wavy stem, which tends to fork rapidly at 

 distances of about 1 cm. apart. The outer of the two short prongs is frequently aborted, 

 leaving a " knee bend " (see p. 31, footnote). It is these bends which give the waviness to the 

 stem. The shortness of the prongs keeps the mass from branching out in any direction far 

 from the chief axial stem. The living layer is about 8 cm. deep ; the dead parts being covered 

 with epithecal film. 



The calicles are small, from 75 to 1 mm., and deep. The walls are thin and zigzag, and 

 descend vertically all round into the calicle. Short, thick septa begin to appear irregularly 

 right from the top edge of the wall, but the radial symmetry of the rest of the internal septal 

 skeleton is obscured. The interseptal loculi are represented by deep open holes, without traces 

 of radial symmetry. The pali are large, but irregular in position and number. 



The section showed an open reticulum. 



The description is based upon my notes of Specimen No. Z 182a of the collection of West 

 Indian Porites in the Paris Museum. It was labelled P. clavaria, as from the "Antilles 

 (Guadaloup)." Though called P. clavaria, this specimen was obviously not the same, either in 

 growth-form or in size of calicles, as Lamarck's type specimen, for a description of which see 

 below, p. 81. 



Again, it shows quite a regular method of forking along its whole length, and yet can hardly 

 be said to be either of the form clavaria or furcata, using these terms to express a diiference, 

 somewhat vague it is true, due chiefly to the distance apart at which forking takes place. 

 Among all the many branching forms from the West Indies I have seen none wliich remind me 

 of this. It is quite different also from other branching forms from the same locality, not only 

 in growth-form but also in calicle formation. 



It is quite clear then from these examples (see also observations to P. Guadalupe Jf) that 

 such vague semi-descriptive terms as clavaria and furcata are quite inadequate for the burden 

 which has been put upon them (see Historical Sketch, p. 3). A comparison of the growth- 

 forms must be undertaken systematically ; for a preliminaiy attempt, see Table III., p. 130. 



26. Porites Guadalupe 6. (P. Guadalupensis sexta.) (PI. II. figs. 2, 3.) 



[Guadalupe, coll. Duchassaing; Turin Museum.] 



Syn. Porites Gtuidalupensis Duchassaing and Michelotti, Les Cor. des Antilles (1860) p. 83. 



Neoporites Guadalupensis Duchassaing and Michelotti, Les Cor. des Antilles Supplement (1864) 

 p. 99. 



Description. — The corallum is encrusting with surface raised into rounded lobes. 

 The calicles are deep, with smooth, wedge-shaped septa. 



