218 E. A. ANDREWS. 



This is obvious in transverse sections (Fig. 14) where the gonad, 

 In this case an ovary, though having the normal relation and 

 position of those found in a common Amphioxus and so developed 

 -as to crowd the digestive organs out of place, is yet found only upon 

 the right side. Longitudinal sections show the entire series of 

 gonads all upon the right side so that there is no question of 

 alternate crowding of left and right gonads into a single series. 

 Both testes and ovaries alike exhibit this asymmetrical develop- 

 ment, though otherwise like those of other lancelets. 



That this single right series corresponds to the right series of 

 Amphioxus without admixture of the left is indicated by its presence 

 as a single right series in the youngest individuals observed. Thus 

 in a specimen 6 mm. long (Fig. 5) the gonads are a single, right 

 series of minute collections of few large cells, the sex as yet un- 

 recognizable, having the same position and character as the early 

 stages of the gonads on right or left of the common Amphioxus as 

 figured by Boveri (25 Fig. 8). 



It is thus evident that the asymmetry of the reproductive organs 

 goes back to an early stage and is probably due to the lack of de- 

 velopment of the left series found in other Acraniata. Whether 

 there is at the first any start of this missing left series cannot be 

 determined at present. 



The gonads differ from those of the known lancelets in being 

 somewhat more numerous on the right side. Thus while the 

 European form has according to Lankester (23) but 26 gonads on 

 the right (and as many on the left) this Bahama form has 29 as 

 seen in Fig.'l. They begin at the fifteenth myotome, gradually 

 increase greatly in size, become consequently crowded together 

 (since each corresponds to a myotome), rather suddenly decrease 

 in size posterior to the branchial region and end anterior to the 

 atriopore by a very small gonad like the first of the series, lying 

 in the forty-third metamere. 1 



No observations were made upon the method of discharge of 

 sexual products, but in sections ova and sperm are found in all parts 

 of the digestive tract, in the pre-oral chamber, stomach, intestine 

 and extreme end of the rectum. In some cases the ova in the 



*In Fig. 1 the correspondence between myotomes and ovaries has not been 

 correctly represented. 



