32 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



sections, and also as an approximately trne-to-natnre dia- 

 gram of the typical structure of the group. The structure 

 of various Appendiculariidse examined whole as transpar- 

 ent objects has been described and figured by Huxley, 

 Gegenbaur, Fol, Eisen, Sanders, Moss, Chun and others, 

 but the method of serial sections has not apparently been 

 applied before to this group, and I do not think any 

 figures of sections have yet been published. 



The size of the specimen was: — length of the body 1.5 

 mm., and length of the ''tail" 4—5 mm. On commencing 

 at the rounded posterior end of the body (see PL IV. fig. 

 9) it is found that the first few sections consist of ovary 

 alone surrounded by a delicate inembrane, the ectoderm. 

 There is no trace of cuticular test on this part of the sur- 

 face. Then, after a few sections, a small crescentic or 

 lenticular piece of testis begins to appear on each side of 

 the ovary and gradually increases in size as it is traced 

 forwards. Consequently in some sections near the pos- 

 terior end (see PL I. fig. 1) the ovary seems to be a single 

 median organ placed between a pair of lateral testes. In 

 a few sections considerably further forward, however, (PL 

 II. fig. 2) we find two lateral pieces of ovarian tissue, 

 while the testis is a single organ. The fact is both are 

 single, but lobed : the ovary being slightly bifurcated at 

 its anterior end and having an overhanging dorsal lobe 

 near its posterior extremity (see PL IV. fig. 9, ov), while 

 the testis consists of two great posterior lateral lobes 

 connected anteriorly and ventrally (PL II. fig. 3, sp.). 



The outlines of the ova are not distinct, but the germinal 

 vesicles and germinal spots are very conspicuous even 

 under a low power (PL I. figs. 1, 2, &c.), while a higher 

 magnification shows them as represented in Plate I. fig. 4. 

 The spermatic tissue in the testis shows merely a number 

 of fine rounded dots in a faintly stained protoplasm, the 



