220 BARKER. 



one-half the depth of the body, and extends from the posterior end of 

 the body to the posterior margin of the pvary, where it bifurcates, one 

 arm passing to the left and one to the right of the ovary; the arms 

 extend cephalad around the oral sucker to the anterior end of the 

 body. The reservoir and arms give off numerous long lateral and 

 deep ventral diverticula, but these do not anastomose. The reservoir 

 terminates behind in a short narrow median canal at the posterior end 

 of the body, which ends in a well-defined excretory pore, terminal in 

 position and nearer the ventral than the dorsal surface. The short 

 excretory canal appears to be lined with cuticula. The entire excre- 

 tory system is filled with a mass of fine globular, gray and golden, 

 glistening particles among which are numerous larger globular bodies 

 which stain a bright blue with methylen blue. 



2. Taxonomy. 



Braun (1901, p. 36) described under the name of Bistominn irrora- 

 tum R. a trematode found in the intestine of a sea turtle, Thalassoch- 

 elys carctta, from New Guinea, which has a number of characters 

 similar to the trematode described in this paper. Looss (1901, p. 558) 

 described a similar trematode found in the stomach of a sea turtle, 

 Thalassockelys corticata, from Triest, which he named Pachypsoivs 

 hmatvs. In a later paper Looss (1902, p. 485), after a careful com- 

 parative study of new adult specimens, as well as the forms described 

 by Braun and by himself, reached the conclusion that all were speci- 

 mens of Bistominn irroratnm Rudolphi, those described by Braun and 

 by himself in his earlier paper being young forms, while those studied 

 by himself later were mature. He accordingly classified all of them 

 as Pachypsohis irrorahts (R.). 



Looss (1902, p. 503) gives the following characters for the genus 

 Pachypsohis, "Mittelgrosse Distomen mit sehr kraftigem, dickem, 

 vorn und hinten abgerundetem, auf dem Querschnitte kurz ovalem 

 Korper. Saugnapfe gross und kraftig, Haut besonders im Vorder- 

 korper mit scheinbaren Biindelen feiner stabchenartiger Stacheln 

 bewaffnet. Darm mit starkem Pharynx, ganz kurzem Oesophagus 

 und Darmschenkeln, die bis auf einige von ihren Angfangstheilen nach 

 vorn abgehende Blindsacke einfach sind. Excretionsblase Y formig, 

 mit bis zum Keimstock reichendem Stamme und bis ins Kopfende 

 sich erstreckenden Schenkeln. Stamm und Schenkel mit massig 

 zahlreichen, weiten und zum Theil wieder gespaltenen Seitenzweigen, 

 die nach der Bauchseite hinabsteigen mit Ausnahme des vordersten 



