6 PALAEONTOLOGY OF CALIFORNIA. 



series of much shorter, or rudimentary rays. The tabulae pass obliquely upwards 

 and inwards from the outer vesicular zone on all sides to the columella, and occa- 

 sionally divide, so as to impart a somewhat vesicular appearance to the interior 

 area. Tbe outer vesicular zone consists of small vesicles, arranged in irregular 

 oblique rows, sloping inwards from the surrounding external wall. 



In the tufted specimens with cylindrical corallites, where the epitheca is well 

 preserved, the surface shows no traces of costal stria?, such as we see so well defined 

 on similar varieties of L. mamillare from the subcarboniferous rocks of the Mis- 

 sissippi valley. From this fact, and the slightly more flexuous appearance of the 

 corallites, I am led to suspect that this form may possibly prove to be a distinct 

 species. If so, I would suggest for it the name L. sublceve. Whether the other 

 form, with crowded angular corallites, presents smooth or striated surfaces, when 

 the corallites separate, I have no means of knowing, there being no specimens in 

 the collection in a condition to show these surfaces. 



Lithostrotion ? Californiense, Meek. 



PL 1, Fig. 2, and 2 a, b, c. 



Corallum apparently growing in small tufts, or probably some- 

 times produced and branching into dendroid forms. Corallites 

 large, cylindrical, or cylindrico-conical, and more or less flexuous. 

 Surface marked by small but distinct wrinkles of growth, and, 

 where the epitheca is well preserved, scarcely visible traces of 

 costal strise. Calices rather deep, circular or a little oval, and 

 bearing within a moderately prominent, somewhat compressed 

 columellar boss. Rays from fifty to sixty-eight, a little flexuous ; 

 about half of them extending to the columella, while the inter- 

 mediate smaller ones only pass about one-third of the way in from 

 the outer wall. Vertical section showing the outer vesicular zone 

 to be bounded by a thin, irregular, inner wall, and composed of 

 small, unequal vesicles, arranged in oblique, irregular rows, 

 sloping inwards ; each row consisting of about six to eight of the 

 vesicles. Tabulae ascending and much divided, so as to form 

 large, irregular vesicles, sloping outwards from the axis. 



The specimens of this species yet obtained are mostly detached corallites, em- 

 bedded in hard limestone, and consequently are not in a condition to show very 

 clearly its mode of growth. As near as can be determined, however, it would seem 

 to have grown in small tufts of a few large diverging corallites, — at first subconical 



