126 INVERTEBRATE ZOOLOGY. 



(c) Cross-section of gastric diverticula, anterior portion ; either sepa- 



rately or in connection with the i)roventicular region of the alimen- 

 tary canal. 



(d) Cross-section of stomach, anterior portion. 



(e) Cross-section of stomach, posterior portion, including a snarl of uri- 



nary tnbules, which will be cut in all planes, longitudinal, cross, etc. 



(f) Cross-section of intestine. 



(g) Cross-section of rectum and rectal glands. 



2. Female reproductive system. 



(a) An ovarial tubule stained in Borax Carmine and mounted whole. 



(Stained specimens maj' be given the student, which may be handled 

 as in 1 (b.) 



(b) Cross-section of a mass of tubules, which will cut them at different 



planes. 



(c) Cross-sections of oviduct, in different places. 



3. Male reproductive system. 



(a) A spermatic tubule stained and mounted whole. 



(b) A longitudinal section of a tubule showing the gradual transforma- 

 tion of the large cells at the apex {spermatoblasts) into the spermat- 

 ozoa. Such a section is very diificialt and often impossible to furnish 

 to an entire class. A cross-section of a mass of tubules will give 

 many details which may be interpreted by reference to a single 

 longitudinal section. 



(c) Cross-section of vas deferens. 



4. Respiratory system. 



(a) Temporary mount, unstained, of a mass of tracheal tubes, to show 



the spiral thread. 



(b) Permanent mount of a stained tulnile to show tlie nuclei of the 



intima. 



5. Nervous system. 



Sections through the brain are beautiful, and show well the arrange- 

 ment of the central cells, but the brains must be dissected out and 

 treated separately, and a single brain will not yield more than ten 

 good sections. 



