388 PROCEEDINGS OF THE ACADEMY OF [May, 



four to six hypodermal cells, the sense hairs of which project outward 

 through an aperture in the cuticula. 



Female genital organs. — In campamilata (Ov., figs. 27, 28), coronetta 

 {Ov., figs. 22, 2.3) and conklini (fig. 25) there is a more or less rounded 

 germarium upon the ventral surface of the trunk; its cellular lining 

 is continued caudad as the oviduct (which serves also as an uterus), 

 and the latter opens as an unpaired tube into the cloaca between the 

 openings of the rectum and the nephridia (figs. 29, 30) . The germarium 

 consists for the greater part of its bulk of a syncytium of yolk cells with 

 large nuclei (Yk.N.) and huge nucleoli; there are some fifteen or more 

 of these cells. At one end of the germarium is a cap of cells with 

 much smaller nuclei, which are ovogonia (Ovg.). As the latter increase 

 in size they are pushed in succession into the oviduct, where the 

 cleavage commences. In conklini and campanulata two or three large 

 ova are found in the oviduct (uterus) at once, in caynipanidaia never 

 more than a single one. In ambigua the germarium has an entirely 

 different form (Ov., figs. 19, 20); it begins proximally upon the dorsal 

 left-hand side of the trunk, extends down that side, then across the 

 ventral region to the right hand of the trunk, and at the latter point 

 the mature ova are found in the oviduct. I could not determine, 

 owing to lack of material, where the ovogonia are placed within this 

 remarkable germarium. 



Body cavity. — This lies beneath the hypodermis, is continued in 

 the coronal lobes, and in the foot as far posterior as the peduncle. In 

 it float masses of minute, brownish, non-cellular corpuscles, which vary 

 in number in different individuals of the same species, and in conklini 

 are always exceedingly numerous and very minute. They are dissolved 

 by alcohol, and the larger of them often appear doubly refractive. 

 They must be metabolic products, probably waste products, but I 

 have never found them within the nephridial lumina. In ambigua 

 when the animal is fully extended and somewhat compressed in life 

 beneath the cover-glass, it appears as if these corpuscles flowed within 

 special channels between the hypodermis and the infundibulum, and 

 like Gosse (1862) I was at first inclined to beheve that there existed here 

 a subhypodermal vascular system. But further study showed that 

 the apparent canals are not fixed structures but simply portions of the 

 general body cavity. 



The immature female. — This stage was studied particularly in 

 ambigua, but the general characteristics are the same in all the species. 

 This free-swimming stage (PL XIX, fig. 21), just hatched from the egg, 

 has only an incipient corona and foot. The other differences from the 



