210 Christmas Island. 



Group ASTE^IDJE. 



Mussa, aff. echinata (Edwards & Haime), 1849. 



Zobophi/Uia echinata, Edwards & Haime, 1849. Mem. Astr.,pt. ii : Ann. Sci. 



nat., Zool., ser. iii, vol. xi, p. 253. 

 Mussa ,, Edwards & Haime, 1857. Hist. nat. Cor., vol. ii, 



p. 337. 



This species is represented in the collection by a fragment 

 (No. 203) 70 mm. high, 65 mm. long, and with the calices 28 mm. 

 wide. The specimen includes two confluent calices, and the walls 

 of the corallum are parallel in horizontal sections. As the upper 

 part of the septa is not shown, its absolute specific determination 

 is impossible. But so far as the evidence goes, the specimen 

 agrees with those collected by the "Challenger" in the Malay 

 Archipelago, and determined by Quelch as M. echinata. The only 

 doubtful point is, that in the transverse sections the septa do not 

 appear to be alternately thick and thin ; but this arrangement 

 is probably masked by the secondary calcification of the specimen 

 during fossilization. 



The Christmas Island specimen was collected from the first 

 inland clijffi at the Zigzag, at the altitude of 90 feet. 



Leptoria phrygia (Ell. & Sol.), 1786. 



Madrepora phrygia, Ellis & Solander, 1786. Hist. Zooph., p. 162, pi. xlviii, 



fig. 2. 

 non Leptoria ,, Edwards & Haime, 1849. Mem. Astr., pt. iii : Ann. Sci. 



nat., ZooL, ser. iii, vol. xi, p. 292. 

 ,, ^e«m5 (now Dana), Edwards & Haime, 1849. Ibid., p. 292. 



The name of this species has been the subject of much confusion, 

 owing to an apparent inconsistency between Dana's figures and 

 description of this species and Z. tenuis (Dana). Milne Edwards 

 and Haime apparently based their diagnoses on Dana's figures, and 

 thus inverted the main characters of the two species; for they 

 describe Z. tenuis as having broader gyri and less crowded septa than 

 L. phrygia, and also as having stouter walls and columella. But 

 Dana does not state the magnification of his enlarged figures, and 

 it therefore appears wiser to base the distinctions between the two 

 species on his diagnoses. He therein states that the gyri of 

 L. phrygia are 2-2^ lines broad, while those of M. tenuis are 

 1^ lines broad. Moreover, in L. phrygia there are from 10 to 12 

 septa to the half -inch, whereas in L. tenuis there are about 20 septa 

 to the half-inch. Edwards & Haime, however, define L. phrygia 

 as having the gyn. 3 mm. broad, against 4 mm. in L. tenuis, and 

 15 primary septa per centimetre, against 8 in L. tenuis. 



