The Embryology of Heterodontus japonicus 



653 



Text-figure 2. 

 A map of the Sagami Sea, the Miura Peninsula, and part of the Gulf of Tokio, showing the position 

 of the Misaki Laboratory in which Dr. Dean worked, and the waters from which his specimens 



of Heterodontus were taken. 



From an old chart compiled by Professor I. Ijama. 



After Gudger and Smith, 19J3, Text-figure 3, page 251. 



conditions under which the observations were made. In the present instance, this 

 information is not so adequate as it would be if Dr. Dean had lived to finish his projected 

 article on the embryology of Heterodontus japonicus; for his written records have come 

 down to us in fragmentary and incomplete form. 



THE SPECIMENS AND THEIR SOURCE 



From Dean's notes, also from Mrs. Dean, we learn that eggs and embryos of Hetero- 

 dontus were obtained in Japan in 1900, 1901 and 1905, while Dean was a guest of the 

 Imperial University of Tokyo; also, collecting was carried on for him during his absences 

 from Japan, in 1903, 1904 and 1906. The material was collected at the Marine Zoological 

 Laboratory of the University (Text-figure 1) situated at Misaki on the Miura Peninsula 

 which projects into the Sagami Sea between Sagami Bay and the Gulf of Tokyo (Text- 

 figure 2). Collecting was done at various times throughout the year. The specimens 

 represented numerous stages from early cleavage to young at the time of hatching, in all 

 about 200 embryos. Of these, the majority were examined living, and notes and draw- 

 ings were sometimes made before the embryos were preserved. 



