ZOOLOGY AND BOTANY, MICROSCOPY, ETC. G41 



on the right side and behind, and sending forward on the left side a 

 dorsal branch which extends to the pericardium. Between the ventral 

 face of the viscera on the left side and the underlying muscle is a space 

 whose interpretation is much disputed ; the author is not prepared to 

 say whether it is a hamioccele or a coelom. He announces the discovery 

 of Haller's sub-radular organ in this limpet. 



Conchometer.* — H. S. Conant describes a simple and apparently 

 valuable instrument which he constructed to facilitate his study of 

 variation in Purpura lapillus. It consists of two parts : — (1) a device 

 for measuring angles at the ends of the shell, and (2) a device for 

 measuring the long axis of the shell and the distance from the apex of 

 the shell to the aperture. About 4000 measurements have been taken 

 with the help of the conchometer ; and so well did they correspond with 

 theoretical considerations, that the writer believes the value of the instru- 

 ment to have been proved. 



New Pteropod.-j- — Harold Heath and M. H. Spaulding describe 

 Cijinbuliopis vitrea sp. n., a form which occurs occasionally in large 

 shoals near the surface in Monterey Bay, California. It differs only in 

 minor points from the two other known species of the genus. 



5. Liamellibranchiata. 



Crystalline Style of Lamellibranchiata4 — S. B. Mitra, as the result 

 of a series of observations on this subject, has come to the conclusion 

 that the enigmatic style of, e.g. Anodon, consists of an active anxio- 

 lytic ferment, that it is secreted as a viscous liquid, probably by the 

 hepato-pancreas, that it is stored up as a flexible solid in the caacum, or 

 in some cases in a compartment of the alimentary canal itself, that the 

 end of it which projects into the stomach is slowly and gradually dis- 

 solved there, and, being mingled with particles of food material, con- 

 verts the starchy portion into a reducible sugar. Its presence in the 

 Lipocephala is to be associated with the absence of special salivary 

 glands. The style is not a reserve of food, nor a product of excretion. 



Arthropoda. 

 a. Insecta. 



Development of Muscid33.§ — W. Noack has made a series of obser- 

 vations on the eggs of Calliphora crytlirocephala and of species of 

 Lucilia. He finds that yolk-cells may originate by immigration of nuclei 

 from the posterior end of the blastoderm, or from nuclei left behind in 

 the yolk before the formation of the blastoderm, both methods occurring 

 in varying forms within the limits of the family. The germ-baud con- 

 sists, in its early stages of development, of three parts, the middle piece, 

 the only part hitherto recognised, and an anterior and a posterior part, 

 stretching respectively towards the anterior and the posterior poles. 

 The middle piece forms the mesoderm only, and has nothing to do with 



* Amer. Nat., xxxv. (1901) pp. GG5-7 (I fig.). 



t Proc. Acad. Nat. Sci. Philadelphia, 1901, pp. 509-11 (1 fig.). 



% Quart. Journ. Micr. Sci., xliv. (1901) pp. r>91-G0:J (1 pi.). 



§ Zeitschr. wias. Zool.. lxx. (1901) pp. 1-57 (5 pis. and 10 figs.). 



