156 A. S. PACKARD, JR.", ON THE 



the cLiily low tides is thus secured, by which the proper exposure of the spawning spot to 

 the development-accelerating heat of the direct rays of the sun is obtained." "The female 

 excavates a depression iathe sand, drops her spawn into it, upon which the male emits the 

 fecundating fluid, and the nest is at once deserted, the parents returning seaward with the 

 retreating tide. By the action of the water the eggs are immediately covered up with 

 sand ; though if the wind be unpropitious, large numbers are often washed up and cast in 

 windrows on the beach, and soon devoured by the many hungry beings of bird, fish, and 

 mollusca kind that always abound." In the harbor of Beaufort, North Carolina, in com- 

 pany with Dr. Elliott Coues, I have observed the Liniulus in pairs buried in the sand at 

 about half tide, and in digging down invariably found the male above the female. On 

 opening the female, ripe eggs were found in several instances during the middle of May. 



The freshly laid eggs measure .07 of an inch in diameter, and are green. While most 

 of them are spherical, others are oblong and a little flattened. In the ovary they are of 

 various hues of green and pink, just previous to oviposition. while the small, immature ones 

 are white. The yolk is dense, homogeneous and sticky, the whole mass on being squeezed 

 out not separating into single cells, which float off in the water of the glass, as in most Crus- 

 tacea. The yolk granules are very small and not easily seen, unless the egg is crushed. The 

 chorion is quite opake, very tough and dense. When ruptured, the torn edges show that it 

 is composed of five or six irregular layers, varying in thickness, of a structureless memlsrane. 



The spermatozoa (PI. iii, fig. 1,) are broad, oval, sometimes contracted before the anterior 

 end, and posteriorly suddenly terminating in a filament about four times as long as the 

 body of tlie cell. The seminal fluid is thin, whitish, and oozes out of the two papilloe situ- 

 ated on the under side of the first pair of abdominal feet. The vas deferens may be 

 traced for over an inch towards the middle of the cephalothorax, but I have not farther 

 traced it, nor has Van der Hoeven,^ who has made the most careful dissection of Liraulus 

 that has yet been published. 



The ovaries, opening by two oviducts ending in two external papillae situated on the 

 under side of the first pair of abdominal feet, have been described by Van der Hoeven, but 

 more fully by Gegenbaur.- The oviducts pass directly upwards to the roof of the carapace, 

 the ovaries spreading over the entire dome of the carapace just above the liver, the subdi- 

 visions or tubes of the ovaries extending to the extreme anterior edge of the carapace, and 

 also passing back into the abdomen. The ovarian tubes are much alike, eggs of all stages 

 of growth, from those but little larger than the original epithelial cells, to others just ready 

 to pass into the oviduct, being intermingled along the tube. The ripe eggs of a large 

 female would nearly fill a half pint vessel. Just previous to oviposition the oviducts 

 are crowded with eggs, which can be squeezed out on slight pressure. On examining a 

 male removed from its mate, I found that at the same time the seminal fluid of the male 

 flows from the papilke on the slightest pressure. There is probably no union of the sexes, 

 the male ejecting his milt while burrowing in the sand attached to his partner by his claws. 



Formation of the Egr/. The smaller ovarian tubes consist of irregular layei-s of epithe- 

 lial cells (PI. Ill, fig. 2, a) irregular in form, though when crowded becoming more or less 

 polyhedi'al, and provided with a distinct nucleus. Away from the edge of the tube the 



' Recherches sur I'llistoirc Natiu-ullc et rAnatomie des Beriicksichtiguiig der Gewebe. Abhandlungen der Nat. 

 I.imules. Par J. Van der Hoeven. Leyde, 1838. Gesellschaft zu Halle, Bd. 4, 1858, p. 229. 



'■^ Anatomische Untersuckung eines Limulus, rait besondere 



