122 MUNSON. [Vol. XV. 



opment, and indeed appeared as if they were more or less 

 decayed. Embryos, however, continued to be produced, and 

 the eggs and sand were removed to Chicago in jars, where the 

 development continued, the evaporated salt water being replaced 

 from time to time with ordinary fresh tap water. After pre- 

 serving as many of the different stages as seemed desirable 

 and no more embryos being hatched, the jars were put to one 

 side and neglected till a few days before Christmas, when a 

 hasty examination showed that the water had evaporated and all 

 signs of life had disappeared. In order to clean the jars they 

 were filled with tap water and allowed to soak over night. The 

 ne.xt day I could scarcely believe my own eyes when I found 

 the bottom of the jars swarming with little Limuli. 



The Ov.\ry. 



I. Position and general appearance. — The ovaries of 

 Limulus (PI. XIII, Fig. 2, o%<) communicate with the exterior 

 by means of two horizontal slits, situated on the posterio-dorsal 

 side of the operculum, on each side of the median line, and ap- 

 proximated to within one-fourth of an inch of each other. Each 

 external meatus {g.o) is guarded by an upper and lower thick- 

 ened lip, that is somewhat prominent externally ; and the orifice 

 is further closed by transverse ridges within. 



From these two openings, the two terminal oviducts, lying 

 beneath the outer integument of the posterio-dorsal surface of 

 the operculum ipp), traverse the proximal part of the opercu- 

 lum, and, proceeding forward, upward and outward, enter the 

 cephalothorax. Here each duct soon divides into two large 

 branches, one of which takes a peripheral direction, while the 

 other takes a course toward the central axis of the body, where 

 it anastomoses with the corresponding branch of the opposite 

 side, in the median line directly above the alimentary canal {al.c). 

 The point of divergence of the central and peripheral branch of 

 each duct is entirely obliterated, giving the two branches the 

 appearance of one continuous tube, in the middle of the ven- 

 tral side of which is inserted the slightly larger terminal duct. 

 Between the point of insertion of the terminal oviduct (ov.d.) 



