REFERENCES. 305 



87 LEUCKART, RUDOLPH, und PAGENSTECHER, ALEX. Unter- 

 suchungen uber niedere Seethiere. Amphioxus lanceolatus. 

 Miiller's Archiv f. Anat. u. Physiol. 1858. pp. 558-569. Taf. 

 XVIII. 



Description of larva; of Amphioxus taken off Heligoland. 

 Drew attention to larval asymmetry, and to the existence of the 

 brain-ventricle (cerebral vesicle). In absence of knowledge of 

 early development their interpretation of many of the structures 

 (especially prasoral pit, mouth, and gill-slits) was incorrect. 

 Latter applies also to Schultze's observations. 



88 LWOFF, BASILIUS. Uber Bait und Entwicklttng der Chorda 

 von Amphioxus. Mittheilungen a. d. Zool. Station. Neapel. 

 IX. 1891. pp. 483-502. One plate. 



Consult this memoir for previous literature on histology of 

 notochord. 



89 LWOFF, BASILIUS. Ueber einige ivichtige Punkte in der Ent- 

 ivicklung des Amphioxus. Biologisches Centralblatt, XII. 1892. 

 pp. 729-744. Eight figures. 



Notes absence of mesodermal " pole-cells." From frequency 

 of mitoses in dorsal ectoderm of gastrula, concludes that the 

 material destined to form dorsal wall of archenteron, from which 

 notochord and myocoelomic pouches arise, grows in from the 

 ectoderm round dorsal lip of blastopore. Hence notochord and 

 mesoderm are essentially derived from ectoderm ! 



90 MARSHALL, A. MILNES. Vertebrate Embryology. London, 

 1893. 



91 MU'LLER, JOHANNES. Uber die Jugendzust'dnde einiger See- 

 thiere. Monatsbericht der konigl. preuss. Akad. der Wissen- 

 schaften zu Berlin. 1851. pp. 468-474. 



First accurate description of larva of Amphioxus, p. 474. In 

 1847 Johannes Mliller obtained a young Amphioxus of 2i- mm. at 

 Helsingfors. He says that the appearance of the gill-slits was 

 peculiar, in that there were two rows of slits in the pharyngeal 

 wall, placed one above the other. In the upper row were five 

 round slits, while the lower slits were vertically elongated and 

 were fourteen in number. He adds that it was doubtful whether 

 it represented the young " Branchiostoma lubricum " or belonged 

 to a new species. 



92 MULLER, WILHELM. Ueber die Hypobranchialrinne der Tuni- 

 katen und deren Vorhandensein bei Amphioxus und den Cyklo- 

 stomen. Jenaische Zeitschrift f. Naturvviss. VII. 1873. PP- 3 2 7~33 2 - 



93 PLATT, JULIA B. Further Contribution to the Morphology of 

 the Vertebrate Head. Anat. Anz.VI. 1891. pp. 251-265. 



