REPRODUCTIVE ORGANS OF KUKENTHALTA BOREALIS. 



189 



They show some variability Avith regard to size and shape. 

 The general plan of the structure is, however, the same. Text- 

 figure 1 shows two varieties of spicules which occur in different 

 colonies. From a comparison it appears that the crystals are 

 arranged about a common point forming like a sphere, studded 

 with irregular, short, sharp points, or they radiate forming a 

 stellate group with rays of irregular length. Sometimes a ray is 

 elongated like a stalk. 



According to the literature, spicules often occur in difierent 

 2[roups of Ascidians, but such structures do not seem to have been 

 observed before in any genus of the Polyzoince. The possibility 

 is, however, not excluded that they have been overlooked, since 

 their presence has been until now unobserved in Kukenthalia. 

 But if this should prove not to be the case, the spicules, having 

 been found only in Kukenthalia, are to be regarded as a charac- 

 teristic of the Arctic form. 



As spicules might be of some value for comparative and 

 systematic studies, an investigation of their occurrence in the 

 diSerent genera of Polyzbince would be of interest. 



The Reproductive Organs. 



A more important i^esult of this investigation is, as will be 

 shown, that the reproductive organs, testes as well as ovaries, have 

 been found in KilJcenthcdia horealis. 



KiiJcentJialia horealis (Gottsch.). 

 Zooid seen from the left side, test partly removed. 



X8. 



rt^. Atrial aperture. Jr. Branchial apertm-e. 6. Bud. 5^. Brood-poucli. ^js. Genital 

 ponch with testis and ovary, ce. Qisophagus. r. Rectum, s. Stomach. 



The organs are in the form of a hermaphrodite structure, the 

 male glands as well as the ovary and the ducts being enclosed in 

 a long, sac-like outgrowth of the mantle which extends into the 

 common test. This outgrowth is here named the genital pouch* 



14* 



