356 CRESSWELL SHEAliER. 



35. Zelinka, C— " Die Gastroctrichen,"' ' Zeit. f. Wiss. Zool.,' Bd. xlix, 



1890, p. 209. 



36. " Stiidieii iiber Radertliiere," ' Zfit. f. Wiss. Zool.,' xliv, 



p. 396, Bd. xlvii, p. 853, Bd. liii, p. 1, 1885-18.92. 



37. • " ijbev Echinodeies," ' Verb. d. deutsclien Zool. Gesell.,' 



4th Jahrssain., 1894, j). 46. 



EXIM.ANATION OF PLATES 17—20. 



lUustratit)^ Mr. Cressvvell Shearer's paper "On the Anatomy 

 of Histriobdella Homari/' 



Lettering. 



ac. Accessory j^lands of the male reproductive apparatus, an. Anal 

 aperture. ap. p. Appendage of the posterior leg. hie. Blastocoelic 

 cavity. hi. m. Muscular organs of jaws. hr. Bridle piece of jaws. 

 hrn. brain, cd. g. 1-cd. g. 3. Ganglia of the caudal region, cl. Clasper. 

 cl. p. Ciliated pit of the head. cce. Coeloni. cce. ep. Cceloniic epithelium. 

 coin. Nerve commissures. /. Fulcrum of jaws. fol. Follicle cells. Jgl. 

 Flagella of the nephridial canals, g. \-g. 5. Ganglia of the ventral neiTe- 

 cord. gl.cl. Gland-cell of clasper. gr.g. Gi-anule gland. ?«<. Intestine. 

 int. 2. Intestine, postei'ior part. j. Jaws. j. 1. Upper ramus of jaws. 

 j.i. Lower ramus of jaws. La. Anterior legs or feet. I. p. Posterior 

 legs. i». Mouth. ■)a.d. Dorsal longitudinal muscles, m.d.p. Median 

 duct of the penis, m. gl. Salivary glands of the mouth, m. oh. Oblique 

 muscles, m.v. Ventral longitudinal muscles, h. <". Ventral nerve-cord. 

 neph.l-ueph.-i: Nephridia. neph.c. Nephridial canals, nepli.h. Head 

 of the nephridium. nepli. o. Opening of the nephridial canal on the 

 external sui-face. neph.s. Spaces on the course of the nephridial canals. 

 OPS. (Esophagus, o. im. Immature ova. or.jy. Orifice of the penis 

 sheath, or. Ovary, ovd. Oviduct, p. Penis. >: Ramus of upper jaw. 

 sprm. Spermatidia. sj^c. Spermatocyte, st. Stomach, t. 1. Median 

 tentacle, f. 2 and /. 3. Lateral tentacles, te. Testis, th. Teeth, v. def. 

 Vas deferens, ves. Vesicula seminalis. vn. c. Ventral nerve-cord. vit. 

 Vitellarium or shell-gland. 



PLATE 17. 



Fig. 1. — Female Histriobdella with eggs. The largest egg shows 

 the presence of a maturation amphiaster x 3(.)0. 

 Fig. 2. — Clasper extended. 



