20 



MR. C. TATE REGAN ON THE 



7. Remarks on the Structure of the Priaphtm. 



Many of the peculinrities of the priapium of Phallostethios, as 

 compared with that of JVeostethus, seem connected witli the two 

 main differences, that the vas deferens opens directly to the 

 exterior instead of into a glandular groove and that a tox- 

 actinium is present. To the absence of a glandular groove may 

 be due the great length of the vas deferens, which coils to form an 

 " epididymis " ; the secretion supplied in Neostethus by the testis, 



Text-fiqure 15. 



t^m.-"\ 

 prri: 





m. d. 



Fhallostethus dunclceri, $ . Transverse sections (X 18) : A, showing tlie intestine, 

 vas del'evens, and ureter entering the priapium, and also the ureter opening to the 

 exterior; B, showing the "epididymis" and the posterior thick-walled portion 

 of the vas deferens above the articulation of the ctenactinium. 



Tc., kiduey; I., liver; s., stomach; i., intestine; u., ureter; v.d., vas deferens;. 

 «., axial bone; ct., ctenactinium; ppm., pleuro-priapial muscle; txm., tox- 

 actinial muscle; c^m., ctenactinial muscle; p«i., muscle of the proctal side; 

 apm., inner muslce of the aproctal side. 



the vas deferens, and the glandular groove comes in Phallostethiis 

 from the vas defei-ens alone. The efferent groove, infrasulcar 

 bones, and pulvinvilar appendage of Neostethus are all directly 

 connected with the glandular groove, and it is not surprising that, 

 they are absent in Phallostethus. 



