530 Bashford Dean Memorial Volume 



there was reason to believe that most of them were done by Japanese artists under his 

 direction. No one, who is familiar with Dean's skill as an artist, will doubt that he was 

 capable of making drawings like those reproduced in this article. But his time at Misaki 

 must have been fully occupied with pushing the collection and preparation not only of the 

 embryological material of his archaic fishes (particularly the more abundant eggs and em' 

 bryos of Heterodontus) but of the other rare zoological materials which he brought back to 

 Columbia University. 



As will be shown later, Chlamydoselachus is an ovoviviparous shark. The embryos 

 with their huge yolk sacs, enclosed in egg capsules, were obtained from the uteri of the 

 female fish newly caught in Sagami Bay. Brought up from depths of from 300-600 fathoms, 

 these embryos presumably could not be kept alive in aquaria. They would be subjected to 

 two greatly changed conditions — a lower pressure and a higher temperature. Further, 

 there is probably a difference in the chemical composition of the surrounding medium 

 when eggs and embryos are transferred from the uterine fluid to sea water. However, 

 in the light of some personal observations, I cannot be sure of this. While a guest-in- 

 vestigator at the Tortugas (Florida) Station of the Carnegie Institution of Washington 

 (1912-15), I found that when the similar thick-shelled intra-oviducal eggs of the nurse 

 shark, Ginglymostoma cirratum (a shallow- water form), were removed from the uterus, 

 opened, and the perivitelline fluid tasted, this was found to be salt. It may be noted here 

 that the cloaca of the nurse shark has a wide external opening and that the common 

 opening into it of the two gravid uteri will often admit three or four fingers. A similar 

 testing of the perivitelline fluid of the uterine egg of a just-caught Chlamydoselachus 

 would be very instructive. 



Even if the factor of chemical composition of the surrounding medium is ruled out, 

 still, because of the great alterations of pressure and temperature, the embryos of Chlamy- 

 doselachus would die quickly. Hence if they were to be drawn alive, the assistance of 

 several skilled artists would be required. In this connection and in corroboration of the 

 idea expressed above, Mrs. Dean states that she clearly remembers that Dr. Dean, while at 

 Misaki in 1900-1901, had the assistance of six artists and that on the second visit (1905) 

 he had four artists making drawings. Mrs. Dean is fortunately able from her diary to 

 give the names of the six artists — one of them being a man named Kuwabara. 



Furthermore, Dean was, at the time of the collection of embryos of Chlamydoselachus, 

 also studying the much more abundant eggs and embryos of Heterodontus which were 

 comparatively easy to procure from shallow water with the aid of divers. 



Since there are many drawings of the young stages of this shark, it is probable that 

 the artists devoted more time to these than to the embryos of Chlamydoselachus. Because 

 of the abundance of valuable Heterodontus material and because the less viable embry- 

 os of Chlamydoselachus must be preserved immediately, it seems probable that figures 

 of the embryos of the frilled shark were drawn at a later date from preserved specimens. 

 I surmise that the colored figures and probably some of the uncolored ones were made at 

 once from fresh specimens at Misaki, or that rough color sketches were made there, and 



