128 CRUSTACEA. 



bearded: if this be so, we do not see why these appendages may not 

 concur in the process of respiration( l), a property confined by Straus 

 to the following ones, because the latter have, besides, a lamina on 

 the inner side, which, with the exception of the two last, is edged 

 with a pectinated series of setce, that according to the figures of 

 Jurine and Randohr are also bearded. The structure of the two last 

 feet is somewhat different, and Randohr distinguishes them by the 

 name of claws. The abdomen, or body properly so called, is divided 

 into eight segments perfectly free between its valves, and is long» 

 slender, recurved at the extremity, and terminated by two small 

 hooks directed backwards. On the superior surface of the sixth 

 segment is a range of four papillae forming indentations, and the 

 fourth presents a sort of tail(i2). The ovaries are situated along 

 the sides between this segment and the first, and open separately 

 near the back into a cavity — matrix, Jurine — formed betwixt the 

 shell and the body, in which the ova remain for some time after 

 they are produced. 



MiJller has given the name of ephippium, or saddle, to a large, 

 obscure, and rectangular spot, which at certain periods, and parti- 

 cularly in summer, appears, after the females have changed their 

 tegument, on the superior part of the valves of the shell, and which 

 he attributes to disease. According to Straus this ephippium pre- 

 sents two oval, diaphanous ampullae, placed one before the other, 

 and forming with those of the opposite side two small oval capsules, 

 opening like that of a bivalve. It is divided, as are also the valves 

 of which it forms a part, into two lateral halves, united by a suture 

 along their superior edge; its interior exhibits another similar, but 

 smaller one, with free edges, provided it be not the superior that is 

 attached to the valves, the two halves of which, playing upon each 

 other as if hinged, present the same ampullae as the exterior lids. 

 Each capsule contains an egg with a greenish and horny shell, other- 

 wise similar to an ordinary ovum, but requiring a greater length of 

 time for its development, and being destined to pass the winter in 

 statu quo. -When the animal is about to change its tegument, the 

 ephippium, as well as its ova, is abandoned with the exuviae, of 

 which it constitutes a part, and which protect them during the 



(1) According to Straus, Cypris and Cythere are not true Branchiopoda, inas- 

 much as their feet are not provided with branchiae; but, as we have already ob- 

 served, the sets and hairs of the two anterior ones and those of the antennae may 

 exercise the functions of branchix as well as those of the palpi and first jaws. 



(2) We omit various details of the organization, because some can only be com- 

 prehended by means of drawings, and others appear common to most of the Bran- 

 chiopoda. 



