Buti.. U. S. B. F., 1909. 



P1.AT1S XLVII. 



Fie. 



ef.^ 



afi/ 







rf-^i 





i'^fi 



^c. 



V;,,"^; 



1^ SSs, X . V 



•'"<(,-«**«SA^« , 



Fig. 3. 



Fig. I.— Part of section parallel to long axis of gill, showing three transverse rows of filaments, cut crosswise, and their double 

 tubular character; a/ and e/, afferent and efferent division of filament. Enlarged 27 times. . ,1 ■! 



Fig. 2. — Diagram of transverse section ot lobster's gill, viewed as a transparency, to show probable course of circulating blood 

 as indicated by arrows; af. v, bianchial stem afferent; ef. v, branchial stem efferent; c r, circular vessel;/, ijiU filament. The 

 relations of the two divisions of the filament to the two divisions of the stem are shown in but few cases only. AH filaments 

 communicate with the stem afferent on the one hand and with the stem efTerent on the other 



I?IG. 3. — Transverse section of oviduct of adult lobster immediately before egg-laying, showing its glandular lining epithelium 

 greatly distended. 



Fig. 4. — Transverse section of oviduct of adult lobster taken immediately after egg-laying, showing the shrunken and vesiculated 

 character of its epitheUmn. 



