334 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiu. 



pigment spots nor any color patterns in the nauplii thus far observed, 

 a condition very diiferent from that found in the nauphi of the Cahg- 

 inse and Euryphorina^. 



The difficulty of hatching these nauplii and rearing them through 

 successive molts is fully as great as in the case of the Euryphorina^, 

 but for a very different reason. In the Euryphorinse the unripe 

 female moved restlessly about the aquarium all the time, and finally 

 crawled up out of the water and remained there until dead and dried; 

 consequently the eggs were dried and killed before they had time to 

 hatch. Here in the Pandarinse, on the other hand, the female is inca- 

 pable of motion, and when placed in an aquarium simply falls to the 

 bottom and lies there inert, usually upon her back. In this way the 

 eggs fail of proper aeration and die almost as surely as when taken 

 oat of the water and dried. Fortunately here also, as in the Eury- 

 phorinse, the hosts are common species of sharks, and a careful exami- 

 nation of the gills and body of these sharks during the parasites' 

 breeding season is practically sure to yield development stages. The 

 eggs for most of the genera hatch about the first of July, so that the 

 best time to look for development stages is during the middle and 

 latter part of the month. 



Those of Perissopus and Pandarus are found upon the external 

 surface, the former on the head and especially around the mouth, 

 the latter in the vicinity of the fins. Those of Nesifims are found 

 attached to the gills, usually near the ends of the gill arches. When 

 the nauplius molts into a metanauplius the second pair of antennae 

 are turned forward side by side, enlarged, and develoi>ed into long 

 prehensile hooks, whereby the larva fastens itself to its host. At the 

 same time the second maxillipeds become organs of attachment and 

 materially assist the second antennae. Both organs retain their 

 function throughout life, the second maxillipeds usually increasing 

 in size and efficiency until they become the chief organs of prehen- 

 sion in the mature adult, while the second antennae diminish some- 

 what, but never lose their function entirely. 



The development, therefore, is very similar to, and in fact almost 

 identical with, that of the Cahginse. And when the metanauplius 

 molts into a chalimus the similarity is further increased by the fact 

 that a frontal filament is formed, very different in length and struc- 

 ture from that found in the Caliginse, but entirely similar in function. 



Hesse claims (1883. p. 4) to have found a larva belonging to the 

 "Pandaridaa," which he calls " Nogagus sinnacii-acliantias" and which 

 he says was attached hj a long and slender frontal filament to its 

 "mother's" carapace. But when his account is examined it is found 

 that very little can be accepted as authentic until further evidence is 

 ffiven. 



