﻿48 MADREPOEARIA. 



This is Dana's description of a small branched Montipore from the Fiji Islands. It was 

 8 to 9 cm. long, with numerous crowded branches 7*5 cm. long. The polyps were yellow, 

 with short tentacles. Near the tips the branches were slightly pitted, the depressions being 

 2 mm. across. 



There are three specimens labelled M. digitata in the National Collection. One is now 

 classed under M. rubra (see above). The two remaining specimens, which are only fragments, 

 are, I think, rightly identified. At first sight they are very unlike one another. One (a) is 

 almost smooth, with each calicle surrounded by a very solid, faintly protuberant ring, while the 

 other (h) has the calicles sunk in slight swellings of the reticulum and moreover not sharply 

 surrounded by any solid ring. Careful examination, however, shows that these two are related. 

 The cross sections are very similar, the form and size of the apertures are alike, and here and 

 there, small patches on each show the peculiar specialisation of the other. 



We may, therefore, add to Dana's description the following. The slight pitting 

 (foveolation) of the surface of the branches may be continued down the stem, or may be 

 replaced by a very different solid ring surrounding the aperture. There are six short, thick, 

 symmetrical septa, leaving a deep, somewhat open fossa ; the interseptal loculi are usually 

 sharply defined. In cross section, the laminate a.xial reticulum is very open but strong, and 

 in marked contrast to the dense white cortical layer, the structure of which out of radiating 

 thickening threads can be easily seen. The transition from the axial to the cortical layer is 

 quite sudden. The axial layer forms the tips of the branches, and it is to be noted that neat 

 star-like caUcles crowd it to the very tip. 



The demonstrable specific identity of these two specimens, in spite of such striking dis- 

 similarity in their surface texture, shakes one's confidence in the validity of some of the 

 foregoing species. Portions of specimen a are hardly distinguished from the type specimen of 

 M. rubra. The sections of the stem in the two cases are, however, in marked contrast. Until 

 we have the definite evidence supplied by longer series of specimens there is no alternative 

 but to describe each striking variation as a new species. 



a, b. Shortland Island, Solomon Islands. Dr. Guppy. 84. 12. 11. 31. 



32. Montipora tortuosa. 



Manopm-a tortuosa, Dana, Zoophytes (1848) p. 509, pi. xlviii. fig. 2. 



Montipm'a tortuosa, Milne-Edwards and Haime, Ann. d. Sci. Nat., (3°) xvi. (1851) p. 66. 



Dcscrijotion. — Corallum ramose, with long branches (10 cm.), thin (6 mm.), bent or 

 tortuous, subcylindrical, slightly compressed. 



Calicles immersed, somewhat scattered, • 5 mm. across. Ccenenchyma perfectly smooth. 



Dana adds that this type (from Singapore) is very like the last, but that the branches are 

 longer and the calicles larger. From the drawing also, the calicles are much more scattered 

 than they are in M. digitata. There is no enlarged figure given of the ccenenchyma. 



There is no certain representative of this coral in the National Collection. See, however, 

 the tliin tortuous specimens of 3f. ramosa ; also the thin tortuous branches of a Montipore 

 entangled in and partly encrusted by specimen a of M. foliosa. 



