284 DR. J. W. GREGORY ON THE PALEONTOLOGY [Aug. 1 895, 



useless. Thus in the case of the epitheca, in a specimen labelled 

 P. furcata which is 134 mm. high, in one branch the epitheca runs 

 up to within 29 mm. of the top on one side, while on the other it 

 ends off 62 mm. from the same point. The shape of the ends of 

 the branches appears at first sight more distinctive, and it is by this 

 character that the specimens have been generally determined • but 

 in a large branching specimen at Cambridge the variation in the 

 compression of the branches varies as follows : — 



Longer diameter _ 9 8 6 7 8 8 

 Wider diameter ~ 15' 15' 13' 7^5' 13' 10* 



The third of these shows the compression of P. furcata, but the 

 fourth is practically circular in section. This one specimen has 

 typical representatives of both the supposed species. 



The last character is the supposed absence of a tubercular colu- 

 mella in P. furcata and its presence in P. clavaria. But there are 

 specimens at Cambridge, Mass., labelled P. furcata, with a well- 

 marked columella. In some the columella can be seen in the older 

 parts of the colony, while it is absent in the newer calices. If this 

 character be of any use, then Pourtales and Quelch have reversed the 

 correct names of the species. Kathbun had previously remarked 

 that the calicinal characters are useless, though he keeps the species 

 distinct : he says that Pourtales's figures of the calicinal structures 

 of clavaria and furcata in the ' Memoir on the Florida Reefs ' (pi. xvi. 

 fig. 14, & pi. xii. fig. 5) would do indifferently for either species. 

 There seems, therefore, no valid distinction between them. In one 

 large mass labelled P. furcata by Pourtales, in some calices there is 

 no trace of a columella, and a circle of pali surround a central space ; 

 in others there is a small columella ; in yet others there is a columella 

 as large as one of the pali. 



Species 2. Porites astreoides, Lamarck, 1816. 



Synonymy : — ■ 



Porites astreeo'ides , Lamarck, 1816, 'Hist. Nat. Anim. s.Vert.'t. ii.p.269; Lesueur, 

 1820, ' Polyp. Lam.' Mem. Mus. Hist. Nat. t. vi. p. 287, pi. xvi. fig. 15 ; Blainville, 

 1834, 'Man. Act.' p. 395, pi. Ixi. fig. 5 ; Ehrenberg, 1834, ' Cor. roth. Meer.' Abb., k. 

 Akad. Wiss. Berlin, 1832, p. 343 ; Lamarck, 1836, op. cit. ed. 2, t. ii. p. 435 ; Dana, 

 1848, ' Zooph. Explor. Exped. Wilkes,' vol. viii. p. 561 ; Duchassaing, 1850, 'Anim. rad. 

 Ant.' p. 17 ; M.-Edwards & Haime, 1860, ' Hist. Nat. Cor.' t. iii. p. 178 ; Verrill, 1864, 

 ' List of Corals,' Bull. Mus. Comp. Zool. vol. i. p. 42 ; Duncan, 1868, ' Foss. Cor. W. 

 Ind.' Quart. Journ. Geol. Soc. vol. xxiv. p. 12 ; Pourtales, 1871, 'Deep-Sea Corals,' 

 111. Cat. Mus. Comp. Zool. no. iv. p. 85 ; id. 1880, ' Flor. Reefs,' Mem. Mus. Comp. 

 Zool. vol. vii. pt. i. pi. xvi. figs. 1-12, 21-22 ; Quelch, 1886, ' Beef Corals,' Zool. 

 ' Chalk' Exped. pt. xlvi. pp. 11, 13, 182 ; Rathbun, 1888, ' Cat. Species Porites U.S. 

 Nat. Mus.' Proc. U.S. Nat. Mus. vol. x. (1887) pp. 354-355 ; Heilprin, 1890, 'Cor. W. 

 Gulf Mex.' Proc. Acad. Nat. Sci. Phil. 1890, p. 305. 



Neoporites astreeo'ides, Duchassaing & Michelotti, 1866, ' Suppl. Mem. Cor. Ant.' 

 Mem. R. Accad. Sci. Tor. ser. 2, t. xxiii. p. 192 ; Duchassaing, 1870, ' Rev. Zooph. 

 Ant.' p. 32. 



Neoporites ineerta, Duchassaing & Michelotti, 1866, ' Suppl. etc' p. 193 ; Duchas- 

 saing, 1870, ' Rev. Zooph. Ant.' p. 32. 



Porites Collegniana (non Michelin), Duncan, 1863, ' Foss. Cor. W. Ind.' pt. i., 

 Quart. Journ. Geol. Soc. vol. xix. p. 437. 



Distribution. Recent : West Indies ; Florida ; Vera Cruz. Fossil : Barbados : 

 Low-level Reefs near Bridgetown; High-level Reefs, Castle Grant (1070 feet); 

 Trinidad, St. Croix ; San Domingo, Nivaje Shale. 



