556 APPENDIX 



10. Examine under a microscope and draw : (a) some of the 

 blood ; (b) if possible the sperm ; (c) in the case of at least one 

 of the vertebrate animals, portions of the tissues fresh and 

 stained ; (d) in the case of small animals, transverse and longi- 

 tudinal sections of the whole body. 

 ii. Examine and draw any larval stages that the animal may 

 have. 

 The following pages contain directions for observing and dissecting, 

 according to the instructions given above, a number of animal types. 

 After working through these in two or three cases, the student should 

 be able to apply the same general directions to the examination of other 

 animals which he may wish to study. 



B. INSTRUCTIONS FOR OBSERVING AND 

 DISSECTING CERTAIN ANIMALS 



The numbers of the items refer to the General Instructions on 

 PP- SS5. 556. 



Frogs are easily found in damp places during a great part of the year, 

 ThB Froe ' 3U ' ™ ' a ' e aul:UInn an( ^ m winter they can most con- 



veniently be obtained from persons who have a stock of 

 them, 1 or from those who are skilled in finding them during their 

 hibernation. 



1. Observe how the animal sits, crawls, jumps, and swims ; the 



movement of the floor of the mouth in breathing ; and if 

 possible the feeding. At the breeding season look for pairs 

 coupled. 



Kill by enclosing in a vessel with a little chloroform. 



2. In a side view, note : head and trunk (no neck or tail) ; fore 



and hind limbs ; mouth, nostril, eye, tympanic membrane 

 (pierce and pass seeker through Eustachian tube to mouth) ; 

 sacral prominence (Fig. 7). 

 Find cloacal opening. 



3a. In hand and foot, number the digits. Note : palmar and 

 plantar surfaces ; absence of claws or nails ; web of foot ; 

 pad on first (really second) digit of hand in male (Fig. 8). 

 b. Open the mouth widely. If the gullet rise, press it back with 

 the handle of a scalpel. Note : maxillary and vomerine 

 teeth ; posterior nares ; eyeballs ; Eustachian tubes ; tongue ; 

 its attachment ; glottis (Fig. 399). 



4a. Lay the frog on its back under water in a dissecting dish ; 

 pin through hands, feet, and top of jaw ; cut the skin along 

 the mid-ventral line, thus opening the ventral lymph sac; 

 free the skin where it is held down on the breast, turn it 

 outwards, and pin. Note : rectus abdominis, pectoral, and 



1 All the animals ordinarily studied in the laboratory can be obtained from dealers, 

 whose advertisements are usually to be found in the pages offfaturt. 



