LIVING BKACHIOPODA. 367 



up to the mature form. These eggs were apparently ripe and ready to be discharged ; 

 the dates upon which the animals were found with eggs in this condition were May 31, 

 June 26, July 12, and August 29. An examination of hundreds of adult individuals 

 revealed the fact that in some, the sinuses were entirely free from eggs, while in others 

 they were packed to repletion. In many, what appeared to be corpora lutea were 

 observed. The appearance of the eggs in the lacunae is shown in 58: li, 3, 4, 6. As 

 previously described, the eggs have been distinctly and repeatedly traced from their 

 dehiscence and escape from the pallial lacunae into the coelomic cavity, their entrance 

 into the nephrostome, their passage, one by one. through the nephridium to their final 

 discharge from the nipple-like exterior openings into the pallial chamber (58 : 4) . Eggs 

 are also found attached to the genital bands and hanging free in the coelomic cavity 

 (56: 1, 3). The eggs are of all sizes as shown in 58: 5, in which a cluster of eggs is 

 represented attached to the genital band. In T. coreanica (57: ll), the pallial sinuses 

 and lacunae when filled with eggs, are deep purple in color (39: 14). The eggs are 

 found in clusters composed of leaf-like processes in radial arrangement (57 : 13) . The 

 clusters were irregularly oval in shape and varied in size (57: 12). In 57: 15, is shown 

 the appearance of one of the radial segments, each leaf holding one or two rows of eggs, 

 with four or five eggs in a row. These leaves were slightly folded in their long diame- 

 ters, the distal edges rounded like a carpenter's gouge. With transmitted light, the 

 leaves were light purple in color, their outer edges tipped with light yellowish-brown, 

 while the eggs were light pink in color (39 : 13) . There were from twenty to twenty-four 

 rows of leaves in each cluster. A side view of one of these masses presents an imbri- 

 cated appearance as shown in 57 : 14. Claparede ('69) figures a group of ovaries in a 

 chaetopod annelid, Pachydrilus verrulosus, which suggests a similar feature in the egg 

 clusters. The arrangement of the egg clusters in T. coreanica is so far unique among the 

 Brachiopoda. 



Testes. 



The long disputed question as to whether the sexes are separate or united in the 

 individual is still a debatable one. That the male and female sexual products arise from 

 the same parts is unquestionable, that they do not arise at the same time in one individ- 

 ual, at least in Terebratulina, is, according to my observations, equally certain. I am 

 strongly inclined to believe that in the Testicardines, .as well as in the Ecardines, the sexes 

 are separate, yet in Terebratulina I cannot positively aver that an individual filled with 

 clusters of spermatozoa, may not at another time be fouud with eggs. I have not been 

 able to detect any differences, external or internal, which would suggest sexual variation. 



