NO. 1105. PROCEEDINGS OF THE NATIONAL MUSEUM. 157 



measures about 0.9 mm. broad bj^ 0.35 min. long. The aiilage of the canals 

 next becomes differentiated into the anlagen of tlie male and the female 

 ducts, and the anlage of the female glands divides into the aulagen of 

 the separate glands. The testicles are now distinct; the segments 

 measure 1 mm. broad by O.Oi mm. long. The ovarial tubes then become 

 distinct, the receptaculum seminis appears and increases in size, and the 

 elongated prostata and the cirrus poucli develop. The developed cirrus 

 l)Ouch measures about O.-'W mm. long by 0.10 mm. broad. In the meantime 

 the testicles have encroached upon the pore side of the segment ante- 

 rior to the ovary. The next change in the segments is brought about 

 by the development of the uterus, which gradually hides the testicles 

 from view. As my material is very poorly preserved, and hence does 

 not stain altogether satisfactorily, the description of the various stages 

 of the uterus must be left for some one who can obtain fresh specimens. 

 IMate YII, fig. 7, represents a segment measuring 2.08 mm. broad. The 

 cirrus pouch with the enclosed inverted cirrus is the only portion of 

 the male organs which is now visible. The female glands have also dis- 

 appeared, but the receptaculum seminis is still present. The uterus 

 tills the entire median field of the segment and appears as a reticulate 

 structure, with dichotomous branches on the periphery. As the ova 

 develop, the boundaries between the different branches of the network 

 become more and more indistinct and the uterus assumes the form of a 

 simple sac (Plate VIII, fig. 1), in which no divisions, or at most extremely 

 fragmentaiy and rudimentary divisions, are visible. The cirrus pouch 

 and the receptaculum seminis are still i^resent. 



Whether this uterus is primarily an actual network, or whether it is 

 originally a simple tube with numerous proximal and distal branches 

 which secondarily anastomose and then gradually disappear to form a 

 common simple sac, can not be stated at present with certainty, but 

 with the data now at hand, I incline decidedly to the latter view. 



The ova measure 52 to 60 /<; the pyriform body measures 12 // broad 

 by 28 // long (horns included). 



In the younger segments no calcareous corpuscles are visible. When 

 the ova in the uterus become more distinct and the partitions in the 

 uterus become less distinct, a few calcareous corpuscles ai)pear in the 

 cortical portion of the segments. As the shells of the ova develop, the 

 calcareous corpuscles become numerous. 



From Eiehm's anatomical description and from my own study, I pro- 

 pose the following as a revised specific diagnosis: 



Diaanosis. — Andrya rhopalocephala (Riehm, 1881), Stiles, 1895: Stro- 

 bila attains 60 to 80 cm. in length by 5 mm. in breadth. Head unarmed, 

 about 1 mm. in diameter, nearly quadrate in apex view, l^eck about 

 1 mm. long. Segments 500 to 600 in number ; active segments slightly 

 broader than long; segments gradually increase in length so that 

 posterior segments are as long as broad ; they may attain 5 to 5.5 mm. 

 in breadth. Genital pores single, near posterior corner of the segment, 



