M. Leuckart on the genus Sacculina. 429 



The ovary consists of a confused mass of numerous caecal 

 tubes; it is therefore probably similar in structure to that of the 

 other parasitic Crustacea. Here and there closed sacs with 

 jagged processes were also met with, just as has recently been 

 described by Glaus in C hondr acanthus^ . 



The ovarian eggs were usually smaller than those of the egg- 

 tubes, and partly also still destitute of a membrane. The ger- 

 minal vesicle could only be rendered distinct with difficulty 

 amidst the numerous larger and smaller oil-drops of the tena- 

 cious yelk. (Considering the relation which subsists, in allied 

 forms, between the ovary and the intestinal membrane, the nu- 

 cleus of our animals might also enclose within it a portion of 

 the intestine.) 



The cement-gland, which accompanies the tubes of the ovary 

 almost everywhere, appears, in its peripheral portion, as a cylin- 

 der of 0*21 millim. in diameter, branched like a stag's horn. 

 Its thick walls are formed by closely approximated cylindrical 

 cells, having a transverse diameter of O'Ol millim. and a length 

 of 0*035 millim., and continued at the centre of their extremity 

 into tail-like processes of considerable length. The contents of 

 these cells consist of a strongly refractive substance. An ex- 

 ternal envelope could not be detected upon these walls ; it ap- 

 peared as if they were only held together by the agglomeration 

 of the cells. 



With regard to the efferent terminations and orifices of these 

 glands, nothing could be ascertained with certainty ; but future 

 observers may probably be led into the right track by the two 

 pairs of lateral orifices discovered by Rathke. Even Rathke 

 regarded one pair of these apertures as the openings of the 

 ovary. As to the second aperture, he was in doubt whether 

 it formed the issue of cement-glands, or of male organs, but 

 decided at last in favour of the latter, although he had no definite 

 ground for this course. 



Nothing can now be urged in favour of the hermaphroditism 

 assumed by Rathke, especially as, in my investigations, no trace 

 of seminal filaments could be discovered. The existence of 

 dwarfed males in the brood-chamber is far more probable, but 

 my investigations in this direction furnished no result. 



EXPLANATION OF PLATE VIL 



Fig. 5. Sacculina inflaia, laid upon its back ; natural size. 

 Fig. C. A portion of the ramified ovisac; natural size. 



* Ueher den Ban und die Entwickelung parasitisclier Crustaceen; 

 Cassel, 1858, p. 13. 



