AMERICAN PARASITIC ARGULID^E— WILSON. 



669 



lar action under normal conditions, and the more or less metamor- 

 phosed contents ))einu- thus discharged to the exterior would give them 

 something of an excretory function. 



The paired eyes are very large, being made up of many spherical or 

 ellipsoidal facets loosely joined together. 



Each eye is inclosed in a transparent blood sinus through which the 

 ])lood circulates freely by means of three or more openings. The 

 facets jut out quite a distance from the pigment, and along the anterior 



he seen as 

 uuch larger 



l)order of the eye, especially in the nirijalops larva', can 

 transparent yellowish globules. They ai'c proportionately 

 than in the adult. 

 Th 



unpaired median 

 eye is situated on the top 

 of the posterior l)order of 

 the l)rain. It consists of 

 an X -shaped pigment body 

 at the junction of three 

 transparent lobes, shaped 

 and arranged Hive the 

 parts of a clover leaf. 

 The pigment has a de- 

 cided reddish tinge. 



No heart is visil)le in 

 any of these larva?, l)ut its 

 place is supplied by sev- 

 eral accessory structures, 

 which produce an active 

 streaming of the blood 

 along practically the same 

 channels as in the adult. 

 The cellular substance be- 

 tween the surfaces of the 



carapace, in the thorax outside of tlie stomach and intestine, and in 

 the abdomen outside the sexual organs, is gathered into little islands, 

 between and around which are blood hicuniv in free conununication 

 throughout the entire body. There is also quite a wide continuous 

 i;)eripheral sinus around the entire body, particularly in the abdo- 

 men. In and out of the lacunae and through the perii)heral sinus the 

 blood is driven by a more or less rhythmical contraction of the 

 following muscles. 



In the abdomen betw^een the p(M'i])heral glands and rudimentary 

 sexual organs and the central intestine lies, on either side, a spindle of 

 very well-developed longitudinal muscles (/. ///., tig. !»). 



Scattered irregularly amongst these are short dorso-ventral. individ- 

 ual muscle libers which are nowhere gathered into bundles {d. v. in.). 



DClMEN OF NEWLY HATCHED MALE LARVA OF AR- 



;i;ai,<ipi?. d. v. m.. uorso-ventral muscles; g., 



•vl>s; //..POSTERIOR WAI.r. OF HEART: /. tH., LONGI- 



MrSCLES: /., TESTIS. 



