FISHERY BULLETIN: VOL. 71, NO. 1 



30' 



20° 30° 40° 50° 60° 70° 80° 90° 100° llQ' 120° 130° 140° 150 ' 



.,_ • - - — jr-TT-T I  —r-- 1  ' ' \ \ <; ''"° 



Thysanopoda 

 tricuspidata 



//// 



distribution of species 

 metonouplius ^jqo 



0° — 



10° 



20°\ 



30° 



20° 40° 60° 80° 100° 120° 140° 



\ 



Figure 9. — The distribution of Thysanopoda tricuspidata and the metanauplius larva in the Indian Ocean based 



on the analyses of Brinton and Gopalakrishnan (in press). 



of T. cristata, notes that the maxillule has an 

 endopod of 2 segments, and again it seems likely 

 that this is also found in the third calyptopis. 



Both T. acutifrons and T. cristata, then, differ 

 from T. tricuspidata in length of described 

 stages, in shape of carapace in calyptopis III, 

 and probably in details of segmentation and se- 

 tation of maxillule and maxilla at least. 



Calyptopes I and II of T. monacantha (iden- 

 tified by E. Brinton) were dissected to compare 

 the endopods of the maxillule and maxilla with 

 those of calyptopes I and II of T. tricuspidata. 

 The calyptopis I had full setation of mouthparts 



and, in both stages, the maxillule, like that of 

 Frost's furcilia, had an endopod of 2 segments 

 with 6 setae and exopod with 4 setae, and there 

 were 3 setae on the endopod of the maxilla. In 

 fact, more setae were found on all of the mouth- 

 parts of the T. monacantha larvae with the ex- 

 ception of the endopod and exopod of the maxil- 

 liped which were like those of the T. tricuspidata 

 calyptopes. 



Information in these few accounts from the 

 literature and from personal observation sug- 

 gest that T. tricuspidata larvae may prove to 

 differ from larvae of other species of the genus 



66 



