60 MADREPOKARIA. 



spicuous in Duchassaing's coral than in that of the ' Challenger ' (cf. PL III. fig. 6, which 

 represents the former with fig. 7a, which is taken from the latter). 



a. Zool. Dept. 86. 12. 9. 365. 



Under this heading, we may provisionally place the Neoporites incerta (PI. III. fig. IV) 

 of these same authors and from this same locality. A magnified photograph of the type was 

 kindly sent by Count Peracca, taken in the Turin Museum. The surface was said to be 

 tuberous or even lobate, therein possibly resembling the ' Challenger ' specimen. The polyps 

 had yellowish-green or even green tentacles, and some specimens seemed to the authors to 

 agree with those described by Lesueur as having tentacles brown at the base, yellow above 

 and with a black spot at the tip. Differences in the skeletal textures, however, are appai-ent, 

 but it is difficult to discover what they are without having the specimens themselves to 

 compare. 



44. Porites St. Thomas 6. {P. Sancti-Thomce sexta.) 



[St. Thomas, coll. Duchassaing ; ? ] 



Syn. Neoporites subtilis Duchassaing and Michelotti, Mem sur les Cor. des Antilles, Suppl. (1864) 

 p. 98, pi. X. figs. 7, 8. 



Description. — The corallum is placentiform, convex above, concave below, pai'tly en- 

 crusting, partly free, supported by epitheca. 



The calicles are very small, like small points and seeming to run together. The septa 

 are smooth, sharply serrate down their axial edges, and with 2 or 3 pali just traceable. 



The colony is a sulphur colour, with yellowish disk and greenish tentacles. 



Turning to the original figures, we see a surface raised into low convex mounds, smooth, 

 of irregular sizes, and separated by narrow concave valleys. The picture of the calicle 

 seems to have been taken from some abnormal double calicle. The coral differs from the 

 P. St. Thomas 5 in its much smaller calicles and in the running together of the latter, 

 which would signify very thin and incomplete reticular walls. 



The name "subtilis" signifies some such textural character differentiating it from the 

 more typical astrseoid Porites. Such a term is quite inapplicable to calicles like those shown, 

 say, in PI. I. fig. 6, and PI. II. fig. 5, which are typical of the astrseoid group (see Table IV. 

 p. 142). 



45. Porites St. Thomas 7. (P. Sancti-Thomce septima.) 



[St. Thomas, coll. Duchassaing ; ? * ] 



Syn. Cosmoporites Iwvigata Duchassaing and Michelotti, M6m. sur les Cor. des Antilles, Suppl. (1864) 

 p. 99, pi. X. figs. 12, 16. 



Description. — The corallum is creeping and encrusting. 



The calicles are small, pentagonal, only slightly pitted, with septa, smooth along the 



• The type was not found by Count Peracca in the Turin Museum. 



