August 12, 1898.] 



SGIEl^GE. 



179 



the anterior region of the organ. The 

 labyrinth is continuous at its anterior 

 median lobe with a short duct which leads 

 to the exterior and opens on a tubercle on 

 the base of the antenna. The large vesicle 

 lies dorsal to the endsac and opens into the 

 duct leading from the labyrinth, but has no 

 direct communication with either the end- 

 sac or labyrinth. The histological structure 

 of the labyrinth and endsac are different 

 and the transition at the point of communi- 

 cation between -their cavities is sharp. 

 The histological structure of the vesicle is 

 very much like that of the labyrinth. 



The first appearance of the organ in the 

 development of the embryo is at the time 

 when the first and second pair of antennsej 

 the mandibles and the first maxillse are 

 marked off. This is approximately 15 to 

 18 days after egg extrusion in summer 

 (August) eggs. The organ at first consists 

 of a differentiation of certain mesodermic 

 cells in the axis of the second antenna near 

 its proximal end. These form the endsac. 

 The lumen is intracellular. About ten 

 days after the first differentiation of the 

 cells which are destined to form the endsac, 

 and at a time when this part of the organ 

 is well marked, there appears an ectoder- 

 mic ingrowth from the ventral face of the 

 second antenna. It is at first solid, but 

 within a short time an intercellular lumen 

 is formed. From this ectodermic ingrowth 

 arise the labyrinth, the duct to the ex- 

 terior, and the vesicle. Thus the two parts 

 arise independently, one from the meso- 

 derm, the other from the ectoderm, and 

 each has characteristic histological condi- 

 tions throughout development. They are 

 both well marked and with distinct lumina 

 at about six weeks (for summer eggs) after 

 egg extrusion, but not until a compara- 

 tively late period of embryonic development 

 (about one month before hatching) do the 

 lumina of these two parts become confluent. 

 At the time of hatching each part is a re- 



latively simple sac, but during larval life a 

 complexity approaching that in the adult 

 organ is reached. This is brought about 

 by a series of evaginations of the walls of the 

 sacs, which later anastomose in a variety of 

 ways, and not by the coiling of a tubule. 

 The histological conditions seem to indicate 

 that the organ is not functional until the 

 beginning of larval life. 



The results obtained as to the develop- 

 ment are in general accord with the condi- 

 tions found by Kingsley in Crangon and by 

 Boutchinsky in Gebia, but are at variance 

 with the development of the organ in As- 

 tacus as described by Reichenbach. 



RAISED SHORE-LINES ON GAPE 3IAYSI, CUBA. 



At the eastern end of the island of Cuba, 

 on and in the vicinity of the promontory 

 known as Cape Maysi, is the most magnifi- 

 cent example of raised shore-lines as seen 

 from the ocean that I know of. They are 

 in the form of huge wave-cut benches ex- 

 tending with perfect regularity and practi- 

 cal horizontality along the face of a long 

 moderate slope and around several promon- 

 tories. "When a profile of the latter is seen 

 from a passing ship the sharp-cut, step-like 

 form readily attracts the attention even of 

 the unscientific observer. The terraces are 

 found one above another at somewhat 

 irregular intervals, are of different degrees 

 of development, possibly as much as a 

 dozen in number, and seem to extend to an 

 altitude of about 1,000 feet above the sea. 

 Above the last terrace visible the land has 

 a topography indicative of sub-aerial ero- 

 sion. The view is backed by the high 

 range of the Copper Mountains, whose crest 

 along this portion of the island is smooth 

 and even compared with most West Indian 

 mountain ranges. 



To the geologist the terraces of Cape 

 Maysi are chiefly interesting because they 

 demonstrate a recent uplift of this part of 

 the island of Cuba. This is singular, be- 



