BOTHR10CEPHALUS LATUS. 99 



making successful injections. Eschricht saw these vessels lying 

 more towards the middle than towards the margins. 



No nervous system has yet been detected. Visual organs, and 

 special organs of touch are wanting, as is also a respiratory 

 system. 



Genitalia. Although the genitalia generally lie singly in each 

 segment, they are sometimes seen double. 



Female sexual organs : a. Vulva, or vagina : a small opening 

 on the hinder margin of the porus genitalis, just over the penis. 



b. Uterus, five, six, or seven alternating horns on each side in. 

 the median line. The uppermost horns are the thickest; then 

 follows a pair of thinner, but very long horns; the rest are thin 

 and small. I call this the uterus, because mature ova are found 

 in this region. In it we distinguish an external cutaneous 

 layer, the capsule of the egg-receptacle, and the inner mem- 

 brane, i. e., a thin sac, twisted round into itself. c. A pigment 

 capsule, = Eschricht's coil (knauel), which secretes the brown 

 colouring matter, and perhaps the shells of the ova ; it is 5 6'" 

 in length, enlarged like a sac in the middle, and opens into the 

 uterus directly at its commencement. Inasmuch as this pig- 

 ment-mass penetrates outwardly through the walls of the 

 capsule, it may, perhaps, be able to give a yellow colour to 

 the agglomerations of calcareous corpuscles, which has led 

 Eschricht to think that these yellow bodies are a peculiar 

 glandular system. d. The true ovaries, with vitellogenes, fyc., 

 are sacs studded on each side of the pigment capsule. They are 

 better recognised in specimens preserved in alcohol than in 

 fresh specimens, and appear to form a convolution of numerous 

 varicose caeca. 



Male sexual organs. a. The opening of the penis is situated 

 on the borders of the first and second quarters of the segment, 

 on the elevation produced by the vesicle of the penis and the thick 

 horns of the uterus, which is flatter in front and more swollen 

 behind. b. The penis, which easily projects from the anterior 

 portion of a, is of equal thickness throughout (i'"), and usually 

 protrudes i //x beyond the margin of a ; the waved margin of the 

 skin forms its prceputium. The glandula praputii of Eschricht 

 are calcareous corpuscles, which are here collected in masses. 



c. Sac of the penis, a vesicle situated in a proper capsule, J'" 

 in length, '" in breadth, between the uppermost thick horns 

 of the uterus, and in which the penis is suspended to a strong, 



