492 Memoir Sears Foundation for Marine Research 



very pale along midzone of back, with a pale spot on top of head and another above pos- 

 terior part of each eyej lower surface black. In some specimens the gradation from the 

 paler upper parts is gradual, but in others the black of the ventral surface extends in narrow 

 triangular zones forward above the bases of pelvics and backward onto the caudal, but 

 interrupted midway of the peduncle by a pale belt; the posterior portions of the dorsal 

 fins and caudal are pale, the tip of the latter dusky or blackish; the inner surface of the 

 anterior part of the upper eyelid is dark brown and densely pigmented. All the specimens 

 examined also show more or less clearly defined black dots sparsely scattered on the top of 

 head and rearward in a single row along the midline of the back to the origin of the caudal, 

 flanked by others in a scattered belt; also two to four lines of short, very narrow black 

 dashes lower down on each side, one line following the lateral line out onto the caudal. 

 Presumably these are luminous organs, and conditions in the closely allied E. lucijer from 

 Japan suggest that in life their centers are of a pearly luster.' 



Size. Length at birth is a little more than 90 mm.; females mature at a little less than 

 300 mm., and males by the time they have reached 250 mm. (see Study Material, p. 489). 

 This, with the fact that the maximum length yet reported for it is 3 1 5 mm. without caudal 

 fin,' shows E. hillianus to be one of the smallest of the sharks. 



Develof mental Stages. Development is ovoviviparous, and females have been taken 

 with as many as five embryos. One in our Study Material contains four young* about 80 to 

 85 mm. long with small yolk sac; these young already show the characters of the adult, in- 

 cluding the coloration; two on one side lie with heads forward, the two on other with heads 

 rearward. 



Habits. Apparently this is strictly a deep-water species, the recorded depths of capture 

 ranging from 208 fathoms down to 392 fathoms. Nothing else is known of its habits. It 

 is not known positively whether or not it is luminous, as are one of the Japanese representa- 

 tives of the genus and E. spinax, although its coloration suggests that such is the case, for 

 the fine black dots on its back and sides (presumably indicating glandular areas) resemble 

 the luminous spots of other luminescent sharks." 



Range. West Indian region and southern Florida to the offing of Chesapeake Bay; 

 probably Bermuda. This little shark is so far known only from Cuban waters, where 

 it is taken quite often on hook and line from deep water^" (here the "Atlantis" took 

 five specimens on one collecting cruise, Matanzas Bay, vicinity of Havana and off the 

 northwest coast) ; from near the Island of St. Kitts; from the Tortugas, Florida," and from 



6. See Oshima (J. Coll. Sci. Tokyo, 27 [15], 1911: x-25) for histology of these organs in E. lucifer. 



7. Longley and Hildebrand, Pap. Tortugas Lab., 24> >94': 3- 



8. Not in very good condition. 



9. For accounts of the luminous organs and phosphorescence of E. sfinax, see Johann (Z. wiss. Zool., 66, 1899: 158) 

 and Burckhardt (Ann. Mag. nat. Hist., [7] 6, 1900: 559) ; for the Japanese E. fusillus and E. frontimaculatus, 

 see Oshima (J. Coll. Sci. Tokyo, 27 [15], 1911) and Schmidt (Proc. Pan-Pacif. sci. Congr., [4.] 5, 1929: 461 ; 

 Trans. Pacif. Comm., Leningr., 2, 193 i ; 9). 



10. Personal communication from Luis Hovvell-Rivero. 



11. Longley and Hildebrand, Pap. Tortugas Lab., }^, 1941 : 3. 



