No. 2.] ANATOMY OF A SPECIES OF PLATVASPIS. 59 



end is moved in an exploring sort of way. Under compression 

 the anterior end is seen to be very mobile, assuming successively 

 an immense number of apparently random shapes with great 

 rapidity and ease. 



External Anatomy. 



The individuals externally resemble (see Figs. 1-3) the 

 form represented in Bronn and Monticelli for P. leiioiri so 

 exactly that at the outset I was hardly sure that the animals 



Fig. i.i — Camera lucida dorsal view of P. anodontae as a transparent object, made from a total 

 preparation in Canada balsam, and by reconstruction from serial sections. 



Fig. 2. — Surface view of tlie ventral surface of /". a«orfo«/<z(?, drawn with a camera lucida. The geni- 

 tal opening was not seen in the animal, but is introduced from the sections (camera lucida). 



are specifically distinct. There is a division of the body into 

 two parts (see Fig. 3), an anterior and dorsal tubular elongate 

 body, resting upon a broad, flat ventral and posterior portion, 



1 The following reference letters are used in all the figures : D., Diaphragm ; 

 Em., Embryos; Ex. P., Excretory pore; G. P., Genital pore ; Int., Intestine; M., 

 Mouth ; M. G. D., Male genital duct ; Nv., Nerve trunk ; Oc, Eye; Ov., Ovary; 

 P., Parenchyma; Sp., Spermary; V., Vagina; Vt., Vitellaria. 



