366 Mr. P. W. Bassett-Smith on 



Tizavd Bank, 7 fatli. On block of coral-rock in associa- 

 tion with specimens of Madrepora, Favia, &c. 



Genus Pocillopora, Lam. 



Tlie examples of this species are fairly numerous ; with 

 one exception, which was found in 26 fathoms, thej have all 

 been obtained in depths under 10 fathoms. The specific deter- 

 mination of these forms is extremely difficult ; tlie definitions 

 given by Lamarck, Edwards and Haime, and other older 

 authors are so general that it is impossible to know wliat tliey 

 include ; and, on the other hand, the variations in the cha- 

 racters of the corallites appear to be so slight in the different 

 forms that they may almost be considered as forming a con- 

 tinuous series separated only by slight modifications in their 

 mode of growth. In the absence of authenticated specimens 

 of known species the list given below can only be regarded 

 as provisional. 



Pocillopora elongata, Dana. 



1848. Pocillopora elongata, Dana, Zoopliytes, p. 531, pi. oO. fior. 4. 



Three specimens from depths of 2-6f fath. 

 Tizard Bank. 



Pocillopora verrucosa, Ell. & Sol., sp. 



1780. Madrepora verrucosa, Ell. & Sol. Nat. Ilij-t. Zooph. p. 172. 

 1836. PociUojjora verrucosa, Lam. Hist, des Auim. sans VertLebr. ed. 2, 

 t. ii. p. 443. 



There are several examples of this species, wliich appears 

 to have flourished all over the reef. Depth 1-10 fathoms. 

 Tizard and Macclesfield Banks. 



Pocillopora hrevicornis, Lam. 



1836. Pocillopora hrcvicornis, Lain. Hist, des Anim. sans Vertebr. t5d. 2, 



t. ii. p. 443. 

 1848. Pocillopora hrevicoriiis, Dana, Zooph. p. 520, pi. xlix. fig. 8. 



Several examples from depths |-1 fath. ; one specimen 

 6^ fath. 



Tizard Bank. 



Pocillopora, sp. 



A single specimen, which in its mode of growth resembles 

 P. hrevicornis ; but the branches are considerably thicker and 

 the corallites somewhat larger. 



Garvan Reef, Tizard Bank, 2 fath. 



