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716 Bashford Dean Memorial Volume 



bluntly, without tendrils. These eggs are deposited on the sea bottom among large rock 

 fragments, or surrounded by rocks. In such situations, some become entangled in sea- 

 weeds, others wedged into crevices between rocks. The egg capsules of Heterodontus 

 galeatus are different, in that the spiral appendages are narrower and end in very long and 

 slender tendrils which become thoroughly entangled among seaweeds. The only records 

 available indicate that living eggs of these species have been taken at the following depths : 

 Heterodontus japoi^icus at 28 feet; H. phillipi at 120 feet or less: and H. galeatus at a depth 

 of 50 feet . There is no record of any direct observations of the process of e gg laying by any 

 species of Heterodont shark in its natural habitat. 



METHOD OF COLLECTING EGGS AND EMBRYOS 



The earliest developmental stages of the egg of Heterodontus phillipi figured by 

 Haswell (1898) were already in late cleavage. These were eggs that had been deposited — 

 as stated more explicitly in a later article by the same author (Haswell, 1916). In this 

 later paper, Haswell described some eggs taken from oviducts ("uteri"). Of these, the 

 two earliest stages were portrayed in a figure which is reproduced as my Text'figure 49a 

 and 49b (page 731). The other eggs, taken from uteri some weeks later, showed more 

 advanced stages of cleavage. 



As previously stated, the eggs of Heterodontus japonicus were collected at all seasons 

 of the year. According to Dean's notes, the greatest numbers of encapsuled eggs were 

 taken during the month of May. They were gathered in small numbers daily, the 

 maximum catch being 21, a number as large as 8 or 10 being uncommon. The greatest 

 number of eggs came from the fishing village of Nagai, between Misaki and Hayama. 



The precise method used in collecting the eggs is not only interesting but is of 

 technical importance. It is well described in Dean's own words: 



In collecting eggs of Cestracion [Heterodontus] divers are indispensable. But these are 

 fortunately numerous in the neighborhood of Misaki, where they are constantly scrutinizing 

 the shore rocks for edible moUusks, especially Haliotis. They have thus an excellent training, 

 for if they can detect these protectively colored Hmpets, they can observe closely enough to 

 collect shark eggs; moreover they are in the habit of examining fissures between the rocks, 

 and they firequently displace stones of considerable size. In general their operations are 

 usually carried on in water of from 12 to 30 feet, though they sometimes exploit a depth of 

 40 feet — all this without the use of special suits, the divers usually swimming to the bottom, 

 remaining under several minutes (2 to 6). They operate usually in pairs, going about in 

 sampans, each boat provided with a screen, and an hibachi (fire-pot) over which the fishers 

 crouch during intervals of rest. A familiar sound near the zoological station at Misaki is the 

 pecuhar whistle of the diver as he expands his lungs before going down. 



Dean states that the eggs are hardy, and are readily kept alive in floating cages. Thus 

 the various embryonic stages may be selected from time to time. The stage of development 

 may be determined with fair precision without the necessity of opening capsules at 

 random, for the character of the capsule gives a clue to the period of incubation. The 



