AND CLASSIFICATION OF WORMS. 9 



granulated protoplasm. Nearly all the cells are developed to about the same extent, but 

 whether or not they are arranged in the form of a branching tubular gland, as in the Ces- 

 tods, 1 I have not been able to determine. The oviduct is larger than the efferent canal of 

 the spermaries, and opens into the shell gland on the underside. 



Fis;. 6 is a diagrammatic combination of several sections, made from camera lucicla 

 drawings of each section, which were traced on thin paper, and then superposed. The 

 drawing corresponds, therefore, to several successive planes. The ovary, Ov., lies furthest 

 forward, and gives off the oviduct Ovd., which is a tube of considerable size ; but the 

 connection of which with the shell gland is not represented in the figure. The shell gland, 

 Sh.g., is the enlarged end of the uterus ; its upper extremity is constricted, and opens into 

 a large spherical vesicle, the spermatotheca, Sp.th., which I have found filled with spermato- 

 zoa in all my specimens. In the individual whose female organs are represented in fig. 6, 

 the whole of the beginning of the uterus was filled with sexual products, so that the course 

 of the tube was comparatively easy to follow. It descends downward on the left, then 

 bends abruptly upwards for a short distance, then downwards again, making a U-shaped 

 curve to the right. In this portion the eggs are already surrounded by a membrane, which 

 increases in thickness as the eggs pass down the uterus. In the shell gland, Sh.g., sperma- 

 ( tozoa, food cells (yolk cells auct.) and egg cells proper, are all intermixed. Passing down 

 . g the uterus we no longer distinguish any spermatozoa, but the food cells gradually become 



»n B :>alled together around the egg cells, and the pellets, as we might call them, thus formed, 

 ...appear at the beginning of the U-shaped bend, above mentioned, surrounded by a thin 

 membrane or shell. 



There is also shown hi fig. 6, Vg., a delicate tube running from the upper or constricted 

 end of the shell gland upwards to the middle of the back. This is the vagina. Its course 

 is incorrectly represented in the drawing, inasmuch as it is really much more irregular than 

 I have figured it, so that great pains were necessary to follow it in my sections, but I finally 

 succeeded in tracing it from the back to the shell gland. I paid particular attention td this 

 point, because it was on account of the existence of a vagina in both orders that the union 

 of the Trematods and Cestods was first proposed. The vagina was first discovered by 

 Blumberg 2 in Amphistomum conicum, and his observations led Stieda 3 to suppose that 

 Laurer's 4 canal, which was long held to connect the testicles with the shell glands, and had 

 been found in thirteen different species of Trematods (cf. Stieda 1. c), was really a vagina, 

 since Blumberg found it to be so in Amphistoma, and Stieda in Distomum liepaticum. 

 Zeller 5 has since described a vagina in Distomum macrostomum, .and found two vaginae in 

 Pohjstomum integerrimum. 6 Independently, and ignorant of these discoveries, Dr. Fitz, 

 in his excellent paper on the anatomy of Fasciola Jacksotii, 7 found the vagina in that 



1 Sommer u. Landois. Ueber Bothriocephalus. loc. cit. , 4 Laurer. Disquisitions anatomicae de Amphistomo con- 

 xxii, p. 57-58. Sommer. Uber Taenia, etc., loc. cit., ico. Diss, inaug. Gryphiae. 1830. 



xxiv, p. 528 und Taf. XLIII, m. 6 Zeller. Ueber Leucochloridium paradoxum. Zeitschr. 



2 Blumberg. Ueber Ampbistomum conicum. Inaug. Diss. wiss. Zool., xxiv. p. 569. 



Dorpat, 1871. 6 Zeller. Weiterer Beitrag zur Kenntniss der Polysto- 



8 Stieda. Ueber den angeblicben inneren Zusammenhang men. Zeitscbr. wiss. Zool., xxvn, p. 249. 



der miinnlichen und weiblicben Organe bei den Trematoden. 7 Fitz. New York Med. Journ. Nov., 1876. 

 Arcbiv fur Anat. Phys. Wiss. Med., 1871, p. 31. 



MEMOIRS BOST. SOC. NAT. HIST. VOL. III. 2 



