8 Roosevelt Wild Life Bulletin 



PAGE 



Figure lo. Cove at Jacob Riis Camp, showing shore conditions at Station 12. 26 



Figure 11. A swimming dock and boat landing at Carr Pond 26 



Figure 12. Characteristics of Alacrohdella decora. A: Details of exterior 

 of anterior and posterior ends showing arrangement of somites 

 (I to XXVII, — X to XXIII inclusive are omitted), annuli 

 (ai-a^, b^-b^, etc.), eyes, segmental sense organs, color mark- 

 ings, suckers, anus, etc. (From Leeches of ^linnesota, 

 Nachtrieb et al, '12). B: Dissection of reproductive organs seen 

 from above, at, atrium or penis sheath; cgl, copulatory^ glands; 

 de, ductus ejaculatorius; ep, epididymis; gXI to gXIV, gangha 

 of the ventral chain; os, ovisac; ov, ovary or ovarian sac; od, 

 oviduct; ti, t2, first and second pairs of testes or testicular 

 sacs; va, vagina; vd, vas deferens. C: Male organs dissected 

 and viewed from the right side. The left sperm-duct retains 

 its natural position; the right is displaced upward, and the 

 dotted line shows the outhne of the atrium before the re- 

 moval of the layer of muscles and prostate glands, ati, 

 internal layer of atrium; de, ductus ejaculatorius; ep, epididy- 

 mis; pg, prostate glands and muscles; p, prostate comua of 

 atrium. (B and C from Hirudin ea of Illinois, Moore, '01) ... . 31 

 Figure 13. Activities of Macrobdella decora. A: resting and swimming 

 positions; (note that the swimming leech is turned on edge). 

 B: attacking and feeding upon a frog which has nearly suc- 

 cumbed to the loss of blood. C: feeding upon frogs' .eggs; 

 two leeches have penetrated the mass and are rapidly cutting 

 the eggs from their envelopes and swallowing them; of the 

 remaining two, one is swimming, and the other exploring 

 while the caudal sucker remains attached. D: a pair of 

 leeches in copulation; this figure represents Philohdella, a 

 southern leech related to Macrohdetla. A, B and C are 



reduced. D is nearty natural size 32 



Figure 14. Egg case and newly emerged young of M. decora; slightl}^ 



enlarged 37 



Figure 15. Leech traps. Three views of box traps; showing from left to 

 right the top, front and interior from the rear; a canvas 

 bait bag is shown in position above the slit-like entrance. 

 The second type of trap is being held with the entrance 



forward 37 



Figtire 16. Sectional diagram of box trap 38 



Figure 17. Diagram of pen trap (third form), showing relation to bank, 

 the entrance, position of bait, and boards and stones to afford 

 concealment 38 



