On new Species o/ Madrepoica m the British Museum. 451 



my opinion, decidedly against tlic union of the Arachnids 

 and Poecilopods. It is indisputable that Limulus has very 

 little in common with the Crustacea (the Trilobites and 

 Merostomata excluded), and that the origin of the Arachnida 

 is enshrouded in thick darkness ; but the facts at our disposal 

 appear rather to warn us against the dissolution of the sub- 

 type Tracheata and the union of creatures so heterogeneous 

 as the marine Poecilopoda and the terrestrial air-breathing 

 Arachnida. 



LVI. — Preliminary Descriptions of new Species o/Madrcpora 

 in the Collection of the British Museum, — Part II. By 

 George Beook, F.L.S. 



When just a year ago I published in this Journal prelimi- 

 nary descriptions of a number of new species of Madrepora^ 

 I anticipated that by the present time a revision of the 

 whole genus would have been ready for press. Consider- 

 able delay has been caused by the acquisition of further 

 collections, particularly of the fine series of specimens from 

 the Great Barrier Reef area collected by Mr. Saville-Kent, 

 and of a further selection of specimens from the Macclesfield 

 Bank, collected by Mr. Bassett-Smith, Surgeon R.N. Before 

 these were received a number of the species now described were 

 diagnosed from specimens in tlie general collection, the distri- 

 bution of which is increased by their occurrence in the 

 newly-acquired material. As the work of revision is not 

 yet complete, I take the present opportunity of giving short 

 descriptions of forty new species. I believe that tiie cha- 

 racters indicated will be found sufficient to distinguish the 

 species, although in some cases this may not at present 

 appear to be the ease, owing to the lack of precision in many 

 of the descriptions of older species. This I hope to rectify 

 as far as possible in the revision of the genus, the publica- 

 tion of which will not, I trust, be further delayed. 



Madrepora amhigua. 



Corallum subhorizontal (? suberect), somewhat flabellate ; 

 branches irregularly confluent, basal parts fused into a solid 

 mass. Branches 1"5 centim. diameter, with a few short 

 arched and blunt divisions on the upper surface. Apical 

 corallites scarcely prominent, 2*5 to 3, rarely 3*5 millim. 

 diameter. Lateral corallites irregular and very unequal, many 

 immersed ; prominent ones chiefly spout-shaped, spreading : 



31* 



