ANATOMY AND PHYSIOLOGY. 
Moll 17 
vesicles (vesicole direttrici) and the first stages of segmentation. Atti 
Acc. Rom. (3) vii. Mem. Sci. fis. pp. 1-54, pis. i.-vii. 
Abstract of Braun’s observations on the development of Bivalves, by 
Bergh, C. B. Ver. Riga, xxiii. p. 120. 
Development of the American Oyster described, by W. H. Brooks, 
Studies Biol. Laboratory at Hopkins University, iv. pp. 1-104, 10 pis. 
[not seen by the Recorder.] 
The development of Teredo described by B. Hatsciiek, Arb. Zool. 
Inst. Wien, iii. pp. 1-44. The fertilized ova (the first changes of which 
are carefully described), are found within the gills of the mother. 
The shell makes its appearance very early, and becomes double, while 
still very thin and almost cuticular in character. The larva in a 
somewhat later stage is a true Trochophore, and the author points out 
the general likeness of Mollueca and Vermes in the first development, but 
he differs from Thering in some other points concerning their relations. 
Abstract in J. R. Micr. Soc. iii. pp. 770-772. 
A few observations concerning the development of the spermatozoids 
in Helix and Paludina, by E. Blomfield, Zool. Anz. iii. pp. 65 & 66. 
11 . Biology. 
Observations on the propagating season and fecundity of various 
Cephalopods and several Gastropods, by Schnitzlein, MT. . z. Stat. 
Neap. ii. pp. 166 & 173. 
Some observations on the appearance of pelagic Mollusca at Naples, 
'chiefiy in spring and autumn ; Schnitzlein, tom. cit. pp. 163-165. 
' Arion eminricorum contains 86, Limax maximus and Doriopsis limhata 
82 per cent, of water ; Krukenberg, Yergl. Phys. Studien, ii. pp. 103 
& 104. 
Clessin, referring to Wiedersheim’s observation on Limncea living 
without water [Zool. Anz. ii. 1879, pp. 572 & 573], remarks that these 
snails are naturally able to survive for some time in wet air without 
water, but he doubts the possibility of accustoming them to it. Mai. 
Blatt. (2) ii. pp. 199 & 200. 
R. P. Whitfield has observed that the progeny of a single indi- 
vidual of Limncea megasoma (Say) produced during confinement in an 
aquarium, exhibited some changes in the soft parts, especially diminu- 
tion in size and disappearance of the male organ. P. Bost Soc. xx. ; 
abstract in Am. Nat. xiv. pp. 51, 52, & 429. W. Dall thinks that this 
diminution in size is due to the want of sufficient and appropriate food. 
Bull. Phil. Soc. Wash. iii. p. 75. 
Mollusca of the depths of lakes; see Geographical Distribution, Middle 
Europe, Switzerland. 
12 . Regeneration. 
J. CarriiSre has published more fully his observations on the renewal 
of the tentacles and eyes in Helix pomatia, horiensis, nemoredis, and 
fruticum ; he gives an historical account of the former experiments by 
Spallanzani and many others in 1768-1779, ascribing the very diflierent 
