626 SmiMAKY OF CURKENT RESEAECHES RELATING TO 



7. General. 

 Zoology of Afghan Delimitation Commission.* — Dr. J. E. T. 



Aitchison lias issued the reports by various specialists on the animals 

 collested by him when attached to the Commission. 290 species belonging 

 to 210 genera, of which 32 species are new, were collected. 



MoUusca. 



Anatomy and Life-history of Australian Mollusea.t — The Eev. J. E. 

 Tenison- Woods has made a study of the MoUusca peculiar to Australia. 

 He considers that, though not separated in an extraordinary way from 

 MoUuscan provinces elsewhere, Australia is entitled to be considered a 

 true Molluscan province, with peculiar features ; these characters are 

 more strongly manifested in proportion as the coast-line is followed to 

 the south : the tropical fauna of the Indian Ocean is extended in many 

 respects far into the extra-tropical portions of the Australian seas. The 

 sense-organs in the tegmentum of the shell, which were first discovered 

 by Prof. Moseley in several genera of Chitonidae, are found in many 

 genera of both bivalves and univalves, such as Trigonia, Area, Venus, 

 Ostrea, Patella, Cerithium, Turbo, &c. In two species of Trigonia the 

 development of the eyes strongly resembles that of the ommatidia of 

 Insects, with which the sense-organs are associated. In connection with 

 these are large ganglia and dependent nerves which are found in the 

 substance of the shell of both bivalves and univalves. The calcareous 

 opercula of some species contain nerve-ganglia and sense-organs, as do 

 probably the chitinous opercula also, to a small extent. The ganglia in 

 the shell-substance are so much larger than any nervous tissue in the 

 softer parts of the animal, that they are apparently the main sources 

 of nervous influence ; these ganglia suggest from their position and the 

 multiplicity of sense-organs that they are really cerebral ganglia. The 

 bivalves examined will, if this is so, be seen to have been erroneously 

 described as acephalous ; they are, if anything, better endowed with a 

 head and brain structure than some univalves. In the mantles of both 

 bivalves and univalves eyes have been found, as well as on the dorsal 

 papillae of some species of OncJiidium. 



In following the life-history of young oysters it was found that the 

 ova are nursed in the gill-chambers of their parent, a fact which may 

 have an important influence upon their cultivation. A similar arrange- 

 ment has been found to exist among certain species of Unio, Siphonaria, 

 Patella, and Acmsea. In very young Siphonaria the lobe of the mantle 

 in front of the head was found to be covered with from 80 to 90 minute 

 spherical and highly refractive bodies which seem to be sense-organs 

 and may have visual powers. 



If all the new facts described in this remarkable paper should be 

 shown to be exactly reported, there will be no doubt that the author 

 deserves the prize awarded for it by the Eoyal Society of New South 

 Wales. 



Eyes of MoUusca. J — Herr J. Carriere has a review of the recent 

 works of Patten and Eawitz on this subject ; as to the former he uses 

 some very hard words, and since the memoir is in many points one in 

 which statements are directly traversed, we will content ourselves with 

 calling attention to it here. 



* Trans. Linn. Soc. Lond., v. (1889) pp. 53-14:2 (■) pis. and 2 maps). 



t Jnurn. and Proc. Roy. Soc. N. S. Wales, xxii. (1888) pp. 106-87 (12 pis.). 



; Arch. f. Mikr. Anat., xxxiii. (1889) pp. 378-402 (1 pl.j. 



