Mr. W. Lonsdale on the Genus Lithostrotion. 473 



part, or where an agreement exists in one particular, there are 

 marked differences in others. Moreover not one of the massive 

 species was so constituted, that it could be considered as possess- 

 ing only specific modifications of the structures observed in the 

 branched ; while all the corals assigned to Lithodendron by- 

 Mr. Phillips have a unity of composition with subordinate dif- 

 ferences ; and among the massive Zoantharia some, at least, have 

 also an aggregate of characters, but different from that of Litho- 

 dendron. Whatever value may be attached to these distinctions 

 by some, the author conceives that they justify the retention of 

 Mr. Phillips's genus — that as respects Lhwyd' s fossil, there is a 

 want of that amount of information which would warrant its 

 being adopted as the basis of a genus — and that he was correct 

 in limiting the term Lithostrotion to Dr. Fleming's second spe- 

 cies, L. ftoriforme. 



The author is unable to review each of the nineteen species 

 described in the ' Archives '; but, that the reader may not have 

 to rest on generic characters only, he begs to offer a few remarks 

 on " Lithostrotion basaltiforme," which is identified with Lhwyd 

 and Parkinson's fossils as w r ell as with Dr. Fleming's Lithostr. 

 striatum. The following are the assigned synonyms and cha- 

 racters [op. cit. p. 441-442). 



I. Lithostrotion, Lhwyd, Lithophyl. Brit. Tchnog. tab. 23. 



2. , Parkinson, Organic Remains, vol. ii. pi. 5. 



fig. 3, 6. 



3. Astrea basaltiformis, W. D. Conybeare and W. Phillips, 

 Outlines Geol. England and Wales. 



4. Astrea arachno'ides, De France, Diet. Sc. Nat. t. xlii. 



5. Lithostrotion striatum, Fleming, British Animals. 



6. Columnaria striata, De Blainville, Diet. Sc. Nat. t. Ix. ; Ma- 

 nuel d'Actinologie. 



7. Lithostrotion striatum, S. Woodward, Synopt. Table, Brit. 

 Org. Remains. 



8. Cyathophyllum basaltiforme, Phillips, Geol. Yorkshire, t. ii. 

 pi. 2. figs. 21, 22. 



9. Columnaria striata, Milne-Edwards, Ann. de la 2 e edit, de 

 Lamarck, t. ii. 



10. Astrea hexagona, Portlock, Report on the Geology of Lon- 

 donderry, pi. 23. fig. 1. 



II. Astrea basaltiformis, ibid. 



12. Lithostrotion striatum, M'Coy, Synop. Carb. Foss. of Ire- 

 land. 



13. Lithostrotion microphyllum'i Keyserling, Reise indasPet- 

 sehora-Land, tab. 1. fig. 2. 



14. Nemaphyllum minus, M'Coy, Ann. and Mag. Nat. Hist. 

 2nd Ser. vol. iii. 



