Nr. 1] ANATOMICAL STUDIES ON ANELASMA AND SCALFEELUM 11 



containing one, or seldom twio nucleoli, and seemingly almost 

 destitute of other chroniatic substanee. Alltogether, we may say 

 that the digestive glands in young specimens convey the impression 

 of being in vivid function, whereas in fullgrown specimens they 

 present distinctly degenerative signs. 



The latter phenomenon probably stands in connection with the 

 development of new alimentary organs, namely the off shoots 

 or f i 1 a m e n t s of the peduncle. These filaments are 

 covered by a homogeneous cuticle, the direct continuation of the 

 cuticle of the peduncle. The cuticle of the filaments is råtner 

 thick nearer the peduncle, but decreases little by little towards the 

 distal part of the filament, and at last disappears entirely, so that 

 the tips of the filaments are naked (pl. II, fig. 11 and 12). In 

 their inner anatomy Geoffroy Smith (1906) speaks of two cell 

 layers; this, howeyer, is not fully oorrect. In the proximal part 

 we may speak of two cell layers; heie the epidermal epithelium of 

 the peduncle is continued for some distanoe, support ing the cuticle 

 of the filament; but this cell laver soon disappears. In the distal 

 parts of the filaments (pl. II, fig. 11, 12) only mesodermal tissue is 

 found as a direct continuation of the mesodermal tissue of the 

 interiør parts of the peduncle. In young specimens, this tissue 

 forms a lacunary, uniserial epithelium, in fullgrown specimens on 

 the other hand, the tissue becomes multiserial; here the outer cells 

 have their nuclei lying near the exteriial cuticle, and this may on 

 superficial investigation convey the impression of two cell layers in 

 the filament. In the centre of the offshoot, an irregular central 

 canal leads from the distal part into the mesodermal, lacunary 

 tissue of the peduncle, and connects here with the lacunæ of the 

 conneotive tissues all over the entire animal. Allhough the obser- 

 vations of Geoffroy Smith may to soine extent be said to be 

 inoomplete, his investigations convey the impression that the struc- 

 ture of the filaments in Anelasma agrees with that of the Rhiz.o- 

 cephal a, and this likewise speaks iin favour of the supposdtion 

 that the filaments also in Anelasma serve as food absorbing organs. 

 Their influence on the tissues of the host, which is described 

 farther below, support this supposition. 



In this connection, the c e m e n t a r y gla n d s must also be 

 mentioned. In free-Iiving barnacles, the ducts of the single gland 

 cells gather into two main canals or ducts, which debouch at the 

 base of the peduncle. In Anelasma I have vainly tried to trace 

 such main canals; the small ducts of the cementary gland cells 

 seem to lead out into the lacunes of the connective tissues, and 

 accordingly to empty their secretions into these lacunes. 



The cementary gland cells are very numerous, and distributed 

 over the upper part of the peduncle at the upper (hinder) side of 



