OF TWO SPECIES OF CYPRIS. 235 



this it will be seen that the bursa copulatrix of Cypris is the 

 reverse of Cypridina Medi terra nea* 



Intromittent organ (Fig. i, c). — This is a paired organ, and is. 

 situated nearly in the centre of the bursa, close under the arches, 

 which receive and carry the spermatozoa previous to its entrance 

 into this organ (Fig. i, l>). It is a dropsical-looking organ, and 

 may be divided into two parts : the posterior and the anterior 

 portions. The former is an ovoid body, its upper end being the 

 broadest, and receives the spermatozoa from the canals. Its 

 downward course is somewhat diagonal, tending towards the base 

 of the bursa. The lower end, where it joins the anterior portion, 

 forms a kind of elbow. There it makes a junction with the ante- 

 rior half, which continues its course in a transverse direction 

 towards the flattened edge of the bursa. The intromittent organ 

 has no nodule, but the termination is somewhat bulbous. Its 

 edges lap over and form a wide, circular orifice, through which the 

 spermatozoa passes. Its length is one-thousandth of an inch and 

 diameter one-two-thousandth of an inch. 



The Spermatozoa. — With respect to the spermatozoa, Mr. 

 Hervey, F.C.S., and myself spent much time, and jointly made 

 some careful investigations in connection with it. It is but fair to 

 state that part of our time was spent in investigating that of C. 

 miniita, and as the histology of one, and more especially as touch- 

 ing the question of mobility, is but the counterpart of the other, I 

 prefer giving an account of our researches under this heading. 

 Professor Huxley, quoting Zenkier, says that " the spermatozoa is 

 totally deprived of mobility."t If by mobility we are to understand 

 active inoveinait, then we join issue and say that, according to our 

 investigations, this statement is incorrect. It is immaterial 

 whether we take the spermatozoa as it exists in the male, or after 

 its injection into the spermatheca of the female. The result is 

 the same — viz., that it possesses very active properties. In dis- 

 secting the animal I use a suture needle with a flat back, and with 

 this, under a dissecting microscope, I gently crush the Cypris just 

 enough to crack the shell. Then with fine pointed needles I tear 



* See Clans. Ostracoda, p. 425, Fig. 336, Sedgwick's translation, 

 f "Anatomy of Invertebrata," page 252. 



