648 P, F. LAIBLAW, 



close together into the penis at their posterior end, and each 

 ending in a small swelling at their forward extremities. 

 They have a total length of about "15 mm. 



The penis is about "1 mm. long, backwardly directed, 

 pyriform, with its apex curved ventrally. Close to the point 

 at which the vesiculas seminales open into it there open also 

 a number of gland cells, which lie immediately ventral to the 

 penis, and pour a secretion into it. The penis itself consists 

 of an outer muscular capsule composed of muscle-fibres 

 running parallel to the long axis of the penis (fig. 7, EcV. 31.). 

 There is an inner muscle layer also composed of a cylinder 

 of longitudinal fibres, attached at one end to the outer 

 capsule at its widest part, and by the other to the eversible 

 part of the penis (fig. 7, I.M.). The outer capsule is con- 

 tinuous with the lining of the cavity immediately within the 

 male aperture. The armature of the penis is very remark- 

 able, and quite unlike that of any previously described form. 

 Its appearance is well shown in Mr. Goodrich's figures (figs. 

 6 a, h). When evaginated the penis is mushroom-shaped, 

 with a convex head. From the margin of the disc of the 

 head extend two lobes, one on either side [4]. From the 

 centre of the head projects a long chitinous spine, whose 

 proximal end is sharply crooked and embedded in the penis 

 (fig. 6, Ch.). The convex surface of the head is covered with 

 meridionally arranged rows of short, slender, slightly curved 

 spines {G.8.). There appear to be some eighteen of these 

 rows, each with ten or twelve spines. 



The large central chitinous spine is tubular at its proximal 

 end, but the tube distally appears to open out into a groove. 

 This spine is an impregnating organ homologous with the 

 "Chitinrohr" described by von Graff [2] for Proboscidge 

 and Mesostoraidse. The spermatozoa probably pass into its 

 tube by an aperture at its proximal end (cf. Proxenetes 

 gracilis, V. Gr. [2,. Taf. viii, fig. 12]). A few muscle-fibres 

 are apparently attached to its base. 



Affinities. — The character of the pharynx is sufficient to 

 indicate that the Rhabdocoele under consideration is allied to 



