KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 63. NIO 9 



Metrocarpa leachi savigny isi6 n. gen. 



Pl. 1, figs. 1—4. Text-figs. 1—4. 



Syn. Botrylloidcs leachi, Savigny 1816. 

 Botryllus leachi, Michaelsen 1921. 



Locality 



West coast of Sweden: Bohuslän, Gullmarf jorden, August 1916, 1917; D:o Gåsö- 

 flakan, July 1920; shallow water; colonies attached to Fucus. Riksmuseum Collection. 



Description. 



Stage I (Text-fig. 1). The first stage is represented by a very young bud, 

 cut off from the parent animal and measuring about 'A* mm. in length. From the 

 figure it appears that reproductive organs occur on both 

 sides of the body. They consist of both male and female t/ 



organs: a small testis and numerous ova represent the 

 ovary of the bud. The groups of ova are not situated °^777 



quite on a level with the testes, but show a tendency to Text-fig. i. Metrocarpa leachi Savigny 

 move backwards and to near the posterior end of the -£f 'J^^^. 'SwE 

 animal. In this stage the testes are only slightly deve- '■ Testis - 



loped, although they are quite distinct. The ova are of 



various sizes, some very small, others very large. Neither testes nor ova are fully 

 developed. Thus, from an examination of this stage it appears that the animal is 

 hermaphrodite, that the male and female organs occur at the same time in the 

 very young bud, and that the organs are separated though situated close to each other. 



The above-mentioned conclusions do not, hovvever, agree with the results of 

 previous investigations on the subject. According to Herdman (1. c. p. 385) the 

 female organs develop first in the young zooid, and when the ova have attained 

 maturity and escaped, the male organs begin to form and are found fully developed 

 in the adult individual only. Herdman has given a morphological explanation of 

 this protogynous arrangement in his description of Botrylloides tyreum, stating there 

 that each zooid produces ova in the genital gland when young, and spermatozoa 

 only when fully developed (1. c. p. 45). 



