The Embryology of Chlamydoselachus 529 



The difficulty of arriving at a total for these eggs and embryos is due to the fact that 

 these notes were made by at least two other persons besides Dean. The table in Dean's 

 handwriting recording 21 adults must have been compiled from various other entries 

 in the notebook labelled Chlamtdoselachus. Finally, the matter is complicated by 

 the fact that the entries cover the catches of the years 1901-1906 inclusive. Here it 

 must be noted that between Dean's departure from Japan in 1901 and his return in 1905, 

 specimens of adults and embryos were collected and sent to him in America. Some of 

 these are listed separately in the notebook referred to. 



There was another small but valuable lot of material made available to Dean. A 

 young Japanese student, T. Nishikawa by name, had in May, 1896, collected eggs and 

 embryos of Chlamydoselachus. By June, 1897, he had finished a brief but interesting 

 paper ("Notes on some embryos of Chlamydoselachus anguineus Garman"). This was 

 published in 1898. In 1900, Dean at Misaki began to get eggs and embryos of the same 

 shark. Nishikawa, having finished with his materials and having published his article, 

 turned over to Dean all his specimens and slides to further Dean's researches. Evidence 

 of this will be adduced in various sections of this article to follow. 



Of the embryological material brought back by Dean in 1901 and 1905, or sent from 

 Japan to him at various times, I have had access to certain embryos of Chlamydoselachus 

 as follows. In the American Museum are six specimens ranging from 190 to 370 mm. in 

 length. In the zoological collection of Columbia University, and loaned to me by Prof. 

 J. H. McGregor, are 13 embryos of various sizes (but none so large as ours), some with 

 and some without yolk sacs ; and five eggs without embryos ; then in addition there are 

 four lots of embryos (mainly very young) collected in 1913, 1914 and 1917- Lastly from 

 the Museum of Comparative Zoology, Cambridge, Massachusetts, there have come 

 through the courtesy of Dr. Thomas Barbour, one small embryo brought from Japan in 

 1907; and an egg with a larger embryo presented by Dr. Dean in 1912. 



THE DRAWINGS AND THEIR AUTHORSHIP 



Found among Dean's records are 55 finished drawings reproduced herein as plates 

 I to VI. These drawings range from a representation of what is evidently an ovarian egg 

 to figures of specimens, male and female, in which the yolk sacs are no longer present. Of 

 the 55 drawings, three are in color and the others are in grey (pencil), but all were pre- 

 pared for reproduction by lithography. These figures were assembled on eleven unnum- 

 bered sheets of heavy cardboard, each plate comprising from one to nine figures. I could 

 not make out any graded arrangement of these drawings as affixed to the sheets which 

 have come to me. With the help of Dr. B. G. Smith, I have endeavored to consolidate the 

 drawings of eggs and embryos and arrange them in sequence so far as is practicable — except 

 that the colored figures have been grouped on one plate. All the drawings of adults have 

 been grouped on the final plate. 



The matter of the execution of the drawings, which form the basis for this article, 

 was at first a puzzle. It seemed probable that some of them were made by Dean, but 



