684 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



a pair of fused dorsal plates, but is without any covering in the other 

 genera. 



Abdomen two-jointed, elongated; the lirst joint much enlarged in 

 Euryphoriis and furnished with a pair of lateral wings; in the other 

 genera without Avings or plates. 



Second maxilli© showing a marked transition from a simple, pointed 

 form in CalUjerla and EJytToj)hora through a blunted, biramose shape 

 in Gloiopotes into a flattened lamina in Alehion^ very similar to that 

 found in the Pandarinje. 



All four pairs of thoracic legs usually biramose and armed with 

 plumose seta?, the lirst pair in Caligeria and the first and fourth pairs 

 in Glo'wpoteH uniramose. The remaining appendages and anal lamina? 

 as in the Caliginte. In development the 3'oung are ne\"er attached by 

 a frontal filament, but by the enlarged second antennse. 



ONTOGENY. 



The life history of the genera belonging to this subfamily is very 

 similar to that in the Caligina?, but differs in several important details, 

 which differentiate the two subfamilies clearly. 



The flattening of the eggs in the egg-strings, the symmetrical 

 arrangement of all the embryos in the same string, and the change of 

 color due to the increase of pigment with advancing development are 

 the same as already described. About ten weeks are required for 

 development in such species as have been observed, and all the eggs 

 in a given string hatch at practically the same time. The issuing 

 nauplius is similar to those of the Caliginte and differs from them 

 chiefly in one particular. 



It is elongate in form, the two ends being about the same size and 

 evenly rounded; there is the same eye-spot and supracesophageal 

 ganglion; the three pairs of appendages, the first antennae uniramose 

 and terminating in two long plumose setse, the second antenni^? and 

 mandibles biramose, the exopod four- jointed, each joint bearing a 

 long plumose seta, theendopod one-jointed and terminating in a single 

 seta. 



The anterior part of the body is transparent and shows the nuiscles 

 which move the appendages, while the posterior part is filled with 

 yolk granules which render it opaque. 



But when we examine the balancers near the posterior end of the 

 body we find them quite different from those which characterize the 

 Caliginse. Instead of a cylindrical base and a broad spathulate tip we 

 have here a longer and more slender appendage tapering directly from 

 base to tip like a very long and acuminate spine. Usually also they 

 stand out at right angles to the central axis and are slightly curved 

 forward. 



