no. 3606 ODONTODACTYLUS — MANNING 15 



Discussion. — 0. scyllarus can be distinguished from all other 

 species in the genus by the presence of only two or three teeth on 

 the dactylus of the claw and the presence of a full complement of 

 carinae on the telson, including two pairs of accessory median carinae. 



Kemp (1913) was correct in synonymizing Gonodactylus bleekerii 

 A. Milne-Edwards, 1868, with 0. scyllarus. Milne-Edwards' account 

 included no mention of features that might distinguish his species 

 from 0. scyllarus, even though he mentioned the latter species in his 

 discussion. A specimen in the Paris Museum collected by Bleeker in 

 Batavia [Djakarta] is probably the type of G. bleekeri although it is 

 not so labelled. It appears to be a normal 0. scyllarus. 



Hansen (1926) was the first to synonymize G. elegans Miers, 1884, 

 with 0. scyllarus. I have examined the types of 0. elegans, two 

 postlarvae or early juvenile females, and concur with Hansen. Al- 

 though the carinae of the telson are poorly developed in those speci- 

 mens, they may be well developed in other specimens of similar size. 



Adults of 0. scyllarus have smaller eyes than adults of any other 

 species in the genus, and, as usual, the eyes in juveniles are comparably 

 larger than in adults. In specimens of the "elegans" stage, the 

 corneal index is 300, whereas in adults it ranges from 470 to 766. 



Odontodactylus scyllarus was originally described by Linnaeus 

 (1758, p. 633) as follows: 



Scylla- 55. C. macrourus articularis, manibus adactylis ventrico- 

 rus. sis rectis angulatis introrsum tridentatis. Mus. Ad. 



Fr. I. p. 86. C. mirabilis. 

 Rumph. mus. t. 3. f. F. G. 

 Habitat in M. Asiatico. 



Statura praecedentis. Thoracis testa latere postico 

 emarginata. Mucronum par pone pedes. 



As Holthuis (1959) pointed out, Rumphius' figure f on plate 3 is 

 0. scyllarus, but figure g is the dactylus of a Gonodactylus since no 

 teeth are shown on the terminal segment. In order to settle the 

 identity of 0. scyllarus, the specimen figured by Rumphius (1705) on 

 plate 3, figure r, is here selected as the lectotype of the species. 



Remarks. — -As in 0. brevirostris (see below), there is some overlap 

 in size between postlarvae and first stage of juveniles; Hansen (1926) 

 commented on this in his account of O. scyllarus. 



Range. — Through most of the Indo-West Pacific in shallow water; 

 it is often found on coral reefs. There are no records from the Red 

 Sea, South Africa, or Hawaii, but there are scattered records from 

 many localities between East Africa and Japan. 



