82 CEYLON PEARL OYSTER REPORT. 



The 3rd, 4th, and 5th abdominal segments each has the posterior part of its dorsal 

 surface raised into a blunt keel. The abdominal segments are all subequal. The 

 telson is long and narrow, and is twice as long as the 6th abdominal segment. It 

 ends posteriorly in a blunt median spine, and is furnished with a lateral spine half- 

 way along each side. The uropods are as long as the telson. 



Family: ALPHEID.E. 



Synalpheus, Sr. Bate, 1888. 



Synalpheus gravieri, Coutiere. 



Synalpheus gravieri, H. Coutiere, 'Fauna of Maldives and Laccadives,' p. 870, 1905. 



Localities : Pearl banks, Gulf of Manaar (Station III.), 7 specimens ; Cheval 

 Paar (Station XLVIIL), 19 specimens; Coral reef, Gulf of Manaar (Station L1V.), 

 2 specimens; west of Periya Paar (Station LXL), 2 specimens, "commensal with 

 dendritic Alcyonarian ;" off Mutwal Island (Station LXVIL), 2 specimens. 



The rostral and orbital spines are equal in length, the latter sometimes being 

 slightly divergent. The rostrum does not reach the end of the 1st joint of the 

 antennular peduncle. The 1st joint of the antennular peduncle is equal to the sum 

 of the other two, the 2nd joint is twice as long as the 3rd. The antennular scale is 

 a little longer than the 1st joint of the jDeduncle. The antennal peduncle is one and 

 one-third times as long as the antennular peduncle. The outer spine of the antennal 

 scale is as long as the antennular peduncle. 



The 3rd pair of legs has a small spine on the dorsal side of the dactylos. The 

 meros has 4 spines on its ventral posterior border. The propodite has about 8 spines 

 on its posterior border. 



General distribution : Maldives, Ceylon. 



Synalpheus laticeps, Coutiere. 



Synalpheus laticeps, Coutiere, 'Fauna of Maid, and Lace.,' p. 874, 1905. 



Localities: Coral reef, Gulf of Manaar (Station LIV.), 1 specimen; deep water off 

 Galle (Station XL.), 4 specimens. 



Orbital spines equal in length to rostrum, but slightly broader. Rostrum shorter 

 than 1st joint of antennular peduncle. First joint of antennal peduncle longest, 

 the 2nd and 3rd joints subequal. Antennular scale a little longer than the 1st joint 

 of the antennular peduncle. The antennal peduncle one and one-fifth times as long 

 as the antennular peduncle. Antennal scale as loug as antennal peduncle. 



Third legs having the dactylos biunguiculate, posterior border of propodite armed 

 with about a dozen spines. 



This species approaches closely to S. biung uiculatus. 



General distribution : Maldives, Ceylon. 



