6 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 123 



only species in which the full complement of carinae (one pair of sub- 

 medians, recurved posteriorly; one pair each of intermediates and 

 laterals) on this somite are not developed in the adult is 0. cultrifer 

 (White). 



4. Sculpture of the telson: In specimens with a TL of less than 

 30 mm all the carinae of the telson may not be present. In postlarvae 

 and early stage juveniles only the median carina and the anterior 

 portions of the submedian carinae may be present. Young specimens 

 also may not exhibit the same degree of development of the carinae 

 as do the adults. In general, the two pairs of accessory median 

 carinae are the last to develop. 



5. Uropod structure: The relative lengths of the two segments 

 of the uropodal exopod may change with increasing size. In juveniles 

 the distal segment may only be one-half or two-thirds as long as the 

 proximal, whereas in adults the segments may be subequal in length. 

 The last movable spine on the outer margin of the uropod is shorter 

 in large specimens than in small ones. The relative lengths also 

 differ in each species; 0. cultrifer is the only species in which the prox- 

 imal segment is always shorter than the distal. 



Four important characters do not change with age: (1) the position 

 of the ocular scales, whether appressed or separate; (2) the setation 

 of the antennal scale; (3) the number of teeth on the dactylus of the 

 raptorial claw; (4) and the presence of posterolateral spines on the 

 fifth abdominal somite. 



Key to Species of Odontodaclylus (Adults) 



1. Ocular scales appressed along midline; telson with 2 pairs of accessory median 



carinae 2 



Ocular scales separate; telson with 1 pair of accessory median carinae . . 4 



2. Fifth abdominal somite unarmed posterolaterally ; telson with longitudinal 



carina extending anteriorly from inner intermediate denticle. 



japonicus, p. 7. 



Fifth abdominal somite with posterolateral spines; telson lacking longitudinal 



carina extending anteriorly from inner intermediate denticle 3 



3. Dactylus of claw with less than 5 teeth; movable spines of uropodal exopod 



broad, inflated distally scyllarus, p. 10. 



Dactylus of claw with more than 5 teeth; movable spines of uropodal exopod 

 tapering distally hawaiiensis, new species, p. 16. 



4. Median carina of telson thin, high; dactylus of claw with less than 5 teeth; 



posteriorly recurved portion of submedian carinae of fifth abdominal 



somite absent cultrifer, p. 18. 



Median carina of telson not noticeably thin or high; dactylus of claw with 

 more than 5 teeth; submedian carinae of fifth abdominal somite recurved 

 posteriorly brevirostris, p. 22. 



