The West American Scieniist. 151 



Galeorhinus zyopterus Jordan and Gilbert. This spec- 

 ies is common in San Diego Bay, but, as with most sharks it is 

 most abundant in the latter part of Summer. Few males ar^ 

 caught; all the specimens examined by us were females. Two 

 individuals taken August 30th, 1889, were with young which 

 average .05 m.in the one, .08 m. in the other. The yolk is alarge 

 spheroid measuring .05X.08 m., and, as in the case of Triads, 

 is surrounded with a loose, delicate membrane. The embryos 

 are colorless. The position of the fins agrees with the adult. 

 All the young, including the largest, have external gills still per- 

 sisting at the gill openings and spiracles. The head is compara- 

 tively shorter and broader than in the adult and the eye much 

 larger. 



Scylliorhinus VENTRiosus Garman. On January 19th, 

 1885, Mrs. E. D. Puell hatched a shark from a flat egg case 

 which she gave to Rosa Smith. The shark may be said to have 

 been "hatched" although the embryo had not absorbed the vitel- 

 line sac and it may have been not quite matured as Mrs Buell 

 pried open the case to let out the shark which was still alive. 

 The shark was provisionally identified as Scylliorhinus ventriosus 

 and the egg case sent to Mr. S. Garman to be figured. 



The young shark difters from the description of the adult sharks 

 in a few very prominent characters, i. e., the caudal is not con- 

 tinuous around the tail, the tip of the tail is margined by a series 

 of flat spines and there is a series of rather strong spinelets along 

 the sides of the back from in front of the second dorsal forward 

 to the head. The central portion of the dorsal fins, the anal and 

 the paired fins dark blue. Back and sides with dark blue double 

 cross bars which are more or less interrupted, those of the tail 

 extending upon both lobes of the caudal. 



Length .085 m. Diam. of yolk about .02 m. Greatest depth 

 .12 of total length; greatest width .14; length ol head .17; width 

 of head .18; length of snout .06; length of branchial area .09; 

 width of mouth .14; distance from snout to first dorsal .49; length 

 of base of first dorsal 07; length of caudal .26; length of pectoral 

 .12; length of ventral . 10. 



C. H. <5f R. S. Eigenma?m, 



OBSIDIAN CLIFF* 



Obsidian Cliff is at the northern end of Beaver Lake, in the 

 Yellowstone National Park, about eleven miles south of Mam • 

 moth Hot Springs. The cliff extends for half a mile, rising from 

 one hundred and fifty to two hundred feet above Obsidian creek 

 and falling away gradually to the north; the upper half is a ver- 

 tical face of rock, the lower portion a talus slope of the same 

 material. 



The southern e nd is formed of nearly vertical columns of black 



*) From the seventh annual report of the U. S. Geological Survey. 



