340 MB. W. T. CALMAK ON THE CHAEACTEES 



appendages, namely, mandibles, first and second maxillae, and 

 maxillipeds. As a matter of fact, however, tlie closest scrutiny 

 of the undissected specimen shows only two pairs of appendages 

 (maxillae) behind the mandibles, and I believe accordingly that 

 the maxillipeds are represented by the succeeding pair of con- 

 spicuous appendages, those, namely, which are borne upon the 

 first free somite. Assuming that these represent the first 

 thoracic appendages, the eighth and last pair will then be 

 represented by what Vejdovsky has considered to be the first 

 abdominal pair; that is to say,, precisely those on which the 

 male genital ducts appear to open, as in the great majority of 

 the Malacostraca. And the additional abdominal somite, of the 

 presence of which we are now assured, still leaves us with the 

 normal number of six abdominal somites. 



The two pairs of antennae are short, composed of few joints 

 not diff'erentiated into peduncle and flagellum. The first pair, 

 or antennules, are uniramous and consist of eight joints. The 

 second pair are seven-jointed, and bear a small unjointed exopod, 

 on the second joint. There is no trace of eyes. 



The mandibles have a serrated cutting-edge and a strong two- 

 jointed (or perhaps three-jointed) palp tipped with two stout 

 curved spines. The two pairs of maxillcB are large, but nothing 

 can be seen of their structure. 



The first seven pairs of thoracic limbs (PI. 20. fig. 3) are of 

 nearly uniform structure. The main axis of the limb in each case 

 is six-jointed. The small coxal joint bears on its outer face a 

 small flattened vesicular appendage interpreted as a branchial 

 plate or epipod. The epipod appears to be borne on a short 

 peduncle, from which it is separated by a transverse articulation 

 or suture. The second or basal joint is long, and carries near its 

 distal end an exopod *, composed of two joints in the case, pro- 

 bably, of the first five pairs and of one joint on the sixth and 

 seventh. The main axis of the limb is continued by a slender 

 endopod of four joints, scantily supplied, like the exopod, with 

 setae. I cannot now find an epipod on the first pair of thoracic 

 limbs (maxillipeds), but it is figured by Vejdovsky, and these 

 appendages do not appear to diflFer in any other respect from the 

 succeeding pairs. The eighth segment behind the head, described 



* Yejdovsky, by an oversight, refers to this as " ein innerer Ast." It is in 

 fact, as his figures show, on the outer side of the limb. 



