Mr. H . J. Carter on the Spermatology of a new species of Nais. 103 



Fig. 48. Ditto, magnitied : a, oesophagus surrounded by glandular masses ; 

 a', ditto, covered with hepatic cells ; b, testes, so-called ; c, so- 

 called fallopian tubes ; /, oviducts ; d, vaginal openings of ovi- 

 ducts ; e, e, o^-isacs, each consisting of several bunches of ova in 

 a string, in each of which bunches one ovum is more developed 

 than the rest, and the posterior in each string the largest; 

 g, g, intestine ; h, segmental organs, double, one on each side ; 

 i, continuation of the worm ; k, floating-cell, more magnified. 



Fig. 49. Cirrus and seta; : a, cirrus ; b, seta;. 



Fig. 51. Large yelk-granules (3-5600ths of an inch long), magnified, to 

 show apparent budding. 



Plate IV. 



Fig. 27. Group of three cells, each of the same size as the sperm-cells, 

 viz. 2-5600ths of an inch in diameter (on the same scale as fig. 5), 

 bearing spermatozoa almost fully developed, attached to their 

 peripher}'. 



Fig. 28. Granular mass (4-5600ths of an inch in diameter), bearing abunchof 

 spermatozoa enclosed in a common membrane ; on the same scale 

 as fig. 5. This membrane, which may be part of the plastic cell- 

 walls of the agglomerated sperm-cells forming the granular mass, 

 was hardly perceptible, in its natural position, from its extreme 

 tenuity and closeness to the spermatozoa ; it is here placed at a 

 distance, to show that there was one. See also in this figure the 

 " abortive vesicles " (?) which appear as granules in the hepatic 

 cell, and another instance of the way in which the spermatozoa 

 become bundled. 



Fig. 29. Nucleated cell 4-5()00ths of an inch in diameter (one of the large 

 vesicles of fig. 26?), containing several daughter-cells, each bear- 

 ing a single spermatozoon (on the same scale as fig. 5). 



Fig. 30. Ditto, ditto, with the spermatozoa liberated and in the parent- 

 cell. 



I am not quite certain of the facts which these two figures ap- 

 pear to substantiate, because the contents of a cell on becoming 

 contracted are apt to mislead. My impression, however, is, that 

 these cells did really contain spennatozoa in the two stages of 

 development represented. 



Fig. 31. Granular mass from the testes of Nais albida, surromided by 

 vesicles, through which the tails of the spermatozoa are pro- 

 jecting. 



Ditto, ditto, more advanced (the vesicles of the centre not intro- 

 duced, that the granular mass may be shown). 

 Ditto (4-5600ths of an inch in diameter), from ditto, with the 

 spermatozoa nearlv developed, showing that it is the head which 

 is attached to the jrranular mass. 



Spermatozoon of Kais albida, fully developed ; 8-5600ths of an 

 inch long. 



Granular mass (o-oGOOths of an inch in diameter) from the testicle 

 of Ampuliaria, bearing, at the same time, spermatozoa, a bile- 

 globule la), and abortive granules (A). 



Ditto (6-5600ths of an inch in diameter), from ditto, bearing two 

 bile-globules. 



Sperm-cell of Ampuliaria, bearing a bundle of spermatozoa with 

 the tails extruded; lo-bftWih of an inch in diameter (on the 

 same scale as fig. 5). 



Fig. 38. Spermatozoon of Ampullariu, 8-5600th5 of an inch long. 



8* 



