316 PROF. P. M. DUNCAN AND ME. W. P. SLADEN ON THE 



Figs. 3-5. Antedon sulcata, Carpenter. 



Fig. 3. Side view of the second and following brachials, with their pinnules ; 

 the second pair of pinnules have their ends broken away. X 3. 



4. A cirrus, X 3. 



5. Dorsal view of the middle part of an arm, X 3. 



Figs. 6, 7. Antedon Milberti, Mull., sp. 

 Fig. 6. Side view of the second and following brachials, with their pinnules, 



X 2. 



7. The same, from another individual, X 2. 



Fig. 8. Antedon Andersoni, sp. n. 



Fig. 8. A cirrus, X 2. 



On the Echinoidea of the Mergui Archipelago, collected for the 

 Trustees of the Indian Museum, Calcutta, by Dr. John 

 Anderson, F.B.S., Superintendent of the Museum. By 

 Prof. P. Martin Duncan, M.B. (Lond.), F.B.S.,E.L.S., and 

 W. Percy Sladen, F.G.S., Sec. L.S. 



[Eead 21st June, 1888.] 



The Echinoidea collected by Dr. Anderson are represented by 

 six species ; and although these are all known forms their 

 association in such a limited area is remarkable, and, so far as we 

 are aware, without precedent. The fact that all the regular 

 Echinids belong to the family Temnopleuridse is especially 

 striking; and the circumstance is the more noteworthy, as in a 

 collection from the Andaman Islands, described last year by 

 Prof. Jeffrey Bell, not a single Temnopleurid is recorded ; and, 

 furthermore, out of nine genera mentioned by him as occurring 

 at the Andaman Islands, not one is represented in the collection 

 placed in our hands from the Mergui Archipelago. 



All the species, with the exception of one, are essentially 

 Tndian-Ocean forms; the majority of the examples, however, 

 present a certain amount of variation when compared with spe- 

 cimen! from other localities which is sufficient to impart a local 

 character. These differences are recorded in the following notes ; 

 but we have not thought them of sufficient importance to warrant 

 in any case their recognition by name as a definite variety. 



