Bull.U. S. F. C. 1895. The American Lobster. (To face page 77. ) 



Plate A. 



BIS. 



Cut 4. — Part of transverse section of exopodite of pleopod 

 of female lobster (the cuticle removed), showing the dis- 

 tribution of the cement glands. July 19, 1891. 



Bl. S, blood sinus, ep, chitlnogenous epithelium. T. G, 

 tegumental eland. 



Cut 5. — Diagram of vertical section through skin, showing a tegumental gland (relatively much smaller than represented) 

 in section and its duct opening to the exterior, also hair pores perforating the cuticle, with the superimposed hairs or set*. 

 The structure of the cuticle or shell is diagrammatically shown. 



Bl. S, blood sinus, cap, capsule of tegumental gland. D, dermis, d, duct of gland, d 1 , mouth of duct. ej>, chitiuogenous 

 epithelium. Gd. C, gland cell. H. p, hair pore. IfM.muscle. JV", nerve, supplying gland. SC, central nerve cell, s', plumose 

 hair, s, simple hair. 2, enamel layer of shell, 2, calcified pigmental layer of shell. 3, calcified non-pigmented layer. 4, inner 

 non-calcified layer of shell. 



Drawn by F. H. Herrick, 



