82 Normentafeln zur Entwicklungsgeschichte der Wirbeltiere. 
No. | Designation Size Preparation Data Body Form Somites 
27 | a) H.E.C. 203 Embryo a) Fixative: Aceto-corrosive. Fore-brain region flexed posteriorly. Mid- | Segmented mesoderm extends to tip of tail, last 
18.0 mm. Section: Transverse, IO ». brain swelling projects anterior to cranial|four or five somites undifferentiated. Myocoel 
Stain: Borax carmine. edge of fore-brain: overhangs ’twixt-brain |confined to dorsal and ventral ends of somites 
b) H.E.C. 204 b) Fixative: Aceto-corrosive. region slightly. Mid-lateral line extends al-|in trunk region. Numerous myofibrils, a few of 
Section: Sagittal, IO u. most to tail. Prominent cloacal protuber- them apparently faintly cross striated. Anterior 
Stain: Borax carmine. ance. somites show distinct rraaoh of ventral “hypo- 
c) H.E.C. 205 c) Fixative: Aceto-corrosive. glossus musculature’” processus. 
Section: Frontal, Io u. 
Stain: Borax carmine. 
28 |a) H.E.C. 1494| Embryo |a) Fixative: Aceto-corrosive. Fore-brain swelling directed a little an-| Outline of somites (as see externally) flatly 
a) 20.6 mm. Section: Transverse, IO u. teriorly. ’Twixt-brain region obscured by E-shaped. In region of pectoral fin, somites 
Stain: Iron haematoxylin, Congo the growth of fore. and mid-brains. Mid-|extend into ventral wall of body cavity. In mid- 
red. brain and hind-brain swellings separated by trunk region, somites extend through dorsal 
b) H.E.C. 1493 | b) 2I.o mm. | b) Fixative: Aceto-corrosive. a shallow groove. Prominent pelvic fin |half of lateral walls of body cavity. A very 
Section: Sagittal, IO u. folds. Lateral line placode extends to level | small cavity in ventral and dorsal tips of somites. 
Stain: Iron haematoxylin, Congo | of pelvic fins. Division of somites into epiaxial and hypoaxial 
red. portions by a deep groove in the external sur- 
face at the mid lateral line. Dermatome distinct 
dorsally and ventrally, but broken down for some 
distance on either side of mid lateral line. Myo- 
blasts distinetly cross striated. Last five or six 
pairs of somites undifferentiated. 
29 H.E.C. 1492 Embryo |Fixative: Aceto-corrossive. Much like preceding embroyo (No. 28).|Somites in mid-trunk region extend nearly to 
24.7 mm. |Section: Transverse, 12 x. Fore-brain swelling, projects a little more | bases of lateral walls of body cavity. In same 
Stain: Iron haematoxylin, Congo red. | anteriorly. Depression between mid-brain |region, dermatome distinct only in dorsal third 
swelling and hind-brain deeper. Lateral| of epiaxial portion of segment and ventral three- 
line placode extends to middle of caudal | fourths of hypoaxial portion. Small cavities in 
fin. extreme dorsal and ventral ends of somites. Last 
six(?) pairs of somites but slightly differentiated. 
30 |a) H.E.C. 1357 Embryo |a) Fixative: Aceto-corrosive. Much like preceding embryo (No. 29). Fore- |Epiaxial and hypoaxial musculature almost di- 
28.0 mm. Section: Transverse, IO y. brain swelling projects farther forward. |vided. Dermatome distinguishable in approxi- 
Stain: Iron haematoxylin, oran- | Depression between mid-brain and hind- | mately dorsal fifth of epiaxial, and ventra) two- 
ge G. { brain swellings less marked. thirds of hypoaxial portion of somite in mid- 
b) H.E.C. 233 b) Fixative: Picro-sulphuric. trunk region. 
Section: Sagittal, 20 ». 
| Stain: Alum cochineal. 
KFO)SELE:G2 22T c) Fixative: Picro-sulphuric. 
Section: Frontal, 20 u. 
| Stain: Alum cochineal. 
31 | a) H.E.C. 202 Embryo |a) Fixative: Aceto-corrosive. Fore-brain swelling directed downward. | Arrangement of muscle bundles into cones quite 
| 34.0 mm. Section: Transverse, 20 y. Mid-brain swelling extends forward but |distinct. Epiaxial and hypoaxial musculature 
| Stain: Borax carmine. little beyond it. almost completely separated. Muscle plates ex- 
b) H.E.C. 362 b) Fixative: ZENKER’S fluid. tend ventrally until nearly meeting in median 
Section: Sagittal, 14 ». ventral line. The dorsal and ventral tips of 
| Stain: Alum cochineal. myotome and dermatome are still epithelial. No 
c) ELE:CHT786 c) Fixative: Aceto-corrosive, myocoel in tips of somites in trunk region. 
| Section: Frontal, 20 v. 
Stain: Borax carmine, iodine green. 
32 | a) H.E.C. 363 Embryo |a) Fixative: ZENKER’s fluid. Main divisions of brain obscured by in-| Muscle cones more compactly arranged than in 
| 37.0 mm. Section: Transverse 20 np. crease of mesenchyma in head region. preceding stage (No. 31). Ventral epithelial tips 
| Stain: Alum cochineal. Short broad rostral process projects for-|of somites smaller. Dorsal epithelial tips obli- 
b) H.E.C. 176 b) Fixative: Aceto-corrosive, ward from ventral surface of head. An- |terated in trunk region, anterior to point a little 
Section: Sagittal, 20 u. lagen of dorsal fin spines. behind posterior dorsal fin. 
Stain: Alum cochineal. 
c) H.E.C. 353 c) Fixative: Picro-sulphuric. 
Section: Frontal, 14 u. 
Stain: Alum cochineal. 
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