CHAPTER X. 

 SEX IN SALPA. 



Those who are familiar with the literature may justly claim that 

 this question has been discussed enough, and I shall not dwell upon it, 

 although I wish to review, very briefly, some of the criticisms which 

 have been published, upon my first paper (The Development of Salpa, 

 Bull. Mus. Comp. Zool., 1876, pp. 291-348), in which I pointed out that 

 since the egg, which is fertilized and developed in the body of the chain- 

 salpa, exists as a true egg in the genital rod before there are any traces 

 of the body of the chain-salpa, this latter cannot be the mother of an egg 

 which is older than itself. 



This view has been fully discussed by several writers, and uni- 

 versally rejected on the following grounds: 



In the year 1877, or a few months after my paper appeared, Salensky 

 (Morph. Jahrbuch, III, pp. 549-601) published a paper on the budding of 

 salpa, in which he affirms that the body which I had called the ovary, 

 and which I have in this paper called the genital rod, gives rise to the 

 cloaca and gill and branchial sac, as well as to the egg; and in a second 

 paper published soon after (3), he says, p. 279, that since he has shown 

 " that the ovary arises from a part of the stolon which I [Salensky] have 

 called the endoderm, and which also represents the rudiment of the 

 branchial sac, this is, in my opinion, enough to show that no definite 

 rudiment for the ovary exists in the stolon, and also to disprove the view 

 that the solitary salpa lays its eggs in the chain-salpaB." 



Salensky has recently, 1891 (17, p. 78), retracted the statement that 

 the genital rod is endodermal, and has admitted that it does not give rise 

 to either the cloaca, the gill, or the branchial sac, so it is plain that his 

 criticism, above quoted, has no basis. 



In 1888 and 1889, Seeliger published two papers, one (11) on the 

 budding of salpa, and another (15) on the budding of pyrosoma, in 

 which he states that the body cavity of the young stolon, in both salpa 

 and pyrosoma, becomes filled by a mass of embryonic, undifferentiated 

 mesoderm, and that from this the nerve tube, the perithoracic tubes, the 

 mesoderm and the genital rod are afterwards differentiated. 



