PERCY SLADEN TRUST EXPEDITION 



IV. SYSTEMATIC. 



Group I. 1. Cyphastrea 



2. Echinopora 



3. Galaxea . 



4. Leptastrea 



5. Diploastrea, no v. 



6. Doubtful Genera 

 Group II. 7. Favia 



8. Goniastrea 



9. Doubtful Genus 



V. LITERATURE OF POLYP ANATOMY 

 VI. EXPLANATION OF PLATES 1—38 . 



PAOE 



38 



48 



58 



■66 



72 



74 



77 



115 



122 



124 



129 



I. INTKODUCTION. 



The morphology of the soft parts of fourteen species of AstrceidcB has hitherto been 

 investigated. Professor Bourne described Mussa corymbosa and Euphyllia glabrescens in 

 1888 (12), and Dr Fowler Galaxea esjjeri in 1890 (48, p. 410). Dr J. E. Duerden in 

 1902, in a memoir on "West Indian Madreporarian Polyps" (32), described some eleven 

 species, viz., Astrangia solitaria Lesueur, Phyllangia americana Ed. and H., Gladocora 

 arhuscula (Lesueur), Orhicella annularis (Ell. and Sol.), Solenastrma hyades (Dana), 

 Favia fragum (Esper.), Dichoccenia stokesi Ed. and H., Isophyllia dipsacea Dana, 

 Manicina areolata (Linn.), Colpophyllia gyrosa (Ell. and Sol.), Meandrina labyrinthica 

 (Ell. and Sol.). He based a new classification of the Madreporaria on a study of 

 altogether sixteen species from which, as far as the Astrcsidoe are concerned, I have 

 entirely to disagree for reasons which will become apparent in the course of this paper. 



At the suggestion of Professor Stanley Gardiner, I undertook, in October 1911, a 

 comparative study of the soft parts of Astreeid Corals in his collections from the Indo- 

 Pacific Ocean, mainly with a view to determining the natural relationships of the genera 

 and species. In April 1912, Professor Gardiner received further preserved coral polyps 

 from the Red Sea and Ceylon. From these collections I have attempted to study those 

 Astraeid genera in which the individual polyps remain separate, the meandering forms 

 being reserved for subsequent examination. Serial sections of about one hundred and fifty 

 polyps from seventy-five colonies were carefully examined, resulting in the determination 

 of seven genera and twenty-seven species. The structure of the soft parts of none of 

 these species had hitherto been described. 



A thorough examination of over 700 Astrseid specimens (possessing distinct corallites) 

 in Cambridge* left me in considerable doubt regarding the scientific value of the so-called 

 generic and specific characters, on which systematists had based their schemes of classifica- 

 tion. The characters usually regarded by them as of value were as follows : (l) the form 

 of growth of the colony (flat or incrusting, massive, branching or irregular with hillocks 

 and valleys) ; (2) the nature of the inter-calicinal peritheca (broad or narrow, grooved or 



* I have had the advantage of discussing these specimens with Prof. Gardiner, who had studied their 

 growth-forms in relation to positions on the reefs. 



