688 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Notes on Myxine.* — F. J.Cole notes a number of interesting points 

 in the anatomy of Myxine. There are two hepatic ducts opening directly 

 into the large gall-bladder. The bile duct itself opens between these 

 two apertures. The gall-bladder of Myxine, therefore, has three openings. 

 In the kidney there is generally no unbroken connection between the 

 so-called pro- and mesonephros of Myxine, although isolated Malpighian 

 bodies occur in the intermediate region. In one specimen the segmental 

 duct was continued forward as a tube in the pronephros. An interesting 

 fact regarding the sexual organs is that there is no protandric herma- 

 phroditism ; every adult is hermaphrodite, but either predominantly 

 male or female. That is, there is either a mature testis and a rudi- 

 mentary ovary, or a mature ovary and a rudimentary testis. The 

 thyroid is a diffuse organ consisting of a number of closed independent 

 alveoli scattered along the whole course of the ventral aorta. The author 

 has traced a connection, by means of fine channels lined by epithelium, 

 between the posterior surface of each afferent branchial artery and the 

 peribronchial sinuses, which suggests the likelihood of other connections 

 between the bloodvessels and the so-called lymphatic spaces in other 

 parts of the body. Several variations in the gills and their vessels are 

 recorded. 



Tunicata. 



Fertilisation in Solitary Ascidians.f — S. Guthers has studied the 

 question of self- and cross-fertilisation in Phallusia mammillata and 

 Ciona intestinalis. The number of cases dealt with was not very great, 

 but nevertheless the results were very consistent. In the case of Phallusia 

 all or nearly all the self-fertilised eggs developed ; in Ciona, none or 

 only a trifling percentage did so. In both animals all or nearly all the 

 cross-fertilised eggs yielded larvae. Phallusia occurs almost always 

 singly, while Ciona is found in groups, whose members are united at 

 the base by the adherent growth of the tests. The opportunities for 

 cross-fertilisation in the former are thus much fewer than in the latter 

 animal. 



INVERTEBRATA. 



Mollusca. 



<*• Cephalopoda. 



Muscles of the Mantle in Cephalopods.| — F. Marceau has studied 

 the structure and the mode of contraction of the muscles of the mantle 

 in Octopus, Sepia, and Loligo. The fibres of the mantle have the form 

 of elongated spindles, with a contractile sheath of fibrillar lamellas 

 coiled in a spiral around the granular nucleated axial column of proto- 

 plasm. Owing to the helicoid structure, and perhaps to a slight hetero- 

 geneity in the fibrils, the mantle-muscles contract almost like ordinary 

 striped muscle. 



Ceylonese Cephalopods.§ — W. E. Hoyle reports on the Cephalo- 

 pods collected by W. A. Herdman off Ceylon. The greatest novelty is a 



* Anat. Anzeig., xxvii. (1905) pp. 323-6. 



+ Arch. Mikr. Anat., B<t 64 (1904) pp. 111-20. 



t Comptes Rendus, cxli. (1905) pp. 279-80. 



§ Ceylon Pearl Oyster Report, Royal Society, Part ii. (1904) pp. 185-200 (3 pis.). 



