RKFEKENCKS. 305 



Z-] Leuckart, Rudolph, und Pagenstecher, Alex. Unter- 

 siic/uiiigeti i'lber niederc Seethiere. Amphioxus lanceolatus. 

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

 XVIII. 



Uescription of larvx- 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 prx'oral pit, mouth, and gill-slits) was incorrect. 

 Latter applies also to Schultze's observations. 



88 LwoFE, Basilius. Ober Jlau und JCntwickliijig der Chorda 

 von /Inipldoxns. Mittheilungen a. d. Zool. Station. Neapel. 

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



Consult this memoir for previous literature on histology of 

 notochord. 



89 L\voFF, BA.srLlu.s. Uebej- einige ivicldige I'linkte in der Ent- 

 ■wkklnng 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. jMilnes. Vertebrate Embryology. London, 

 1893. 



gr MiiLLER, Johannics. Uber die Jiigendzustiinde einiger See- 

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

 schaften zu I?erlin. 185 1. pp. 468-474. 



First accurate description of larva of Am]jhioxus, p. 474. In 

 1847 Johannes iMUller obtained a young Amphioxus of 2 J 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 u])per row were Jive 

 round slits, while the lower slits were vertically elongated and 

 vit\-(t fourteen in number. He adds that it was doubtful whether 

 it represented the young " Branchiostoma lubricum " or belonged 

 to a new species. 



92 MliLLiiR, WiLHELM. Ueber die Hypobranchialrinne der Tuni- 

 katen nnd deren Vorhandensein bci Amphioxus und den Cyklo- 

 stomen. Jenaische Zeitschrift f. Naturwiss. VII. 1873. PP- 3-7-332- 



93 Platt, Julia B. E'urther Contribution to the Aforpholiigy of 

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



