ix, d, 4 Cowles: Palaemons of the Philippine Islands 373 



flattened at the posterior end, is much shorter than the carpus 

 (1:1.57). The dorsal and ventral surfaces of the ischium 

 each present a median longitudinal groove. The lengths, in 

 millimeters, of the parts just described are as follows: Propodus, 

 33.5; finger, 12.5; palm, 21; carpus, 26; merus, 16.5; ischium, 

 11 ; total, 87. 



The telson of this specimen ends in a subacute spine. The 

 externolateral spines do not extend to the end of the telson, and 

 the internolateral spines extend with about half their length 

 beyond the tip. (See below, description of telson of smaller 

 specimens.) 



Patches of poorly developed spines are present on the an- 

 terior part of the carapace. Similar spines are seen on the 

 ventral and lateral parts of the pleura, the dorsal surface of 

 the sixth somite, and the exposed parts of the dorsal and ventral 

 surfaces of the uropods and the telson. These spines are espe- 

 cially numerous on the last three structures named. The is- 

 chium of the first legs and the distal segments of the third, 

 fourth, and fifth legs are covered with very fine spines, which 

 are scarcely stronger than stiff hairs. The immobile finger, 

 palm, carpus, merus, and ischium of the chelipeds are armed 

 with short blunt spines, which are larger in size and fewer in 

 number on the inner than on the outer surface of these seg- 

 ments. The mobile finger is spineless. "Linear spaces" cannot 

 be seen. 



Rostrum and peduncle of first antenna. — An examination of 

 the 72 specimens in our collection shows that the rostrum may 

 extend as far as the tip of the peduncle of the first antenna, 

 may extend slightly beyond it, or may fail to reach it. In no 

 case does the rostrum extend to the tip of the antennal scale, 

 and there is no indication that the rostrum decreases in pro- 

 portional length with reference to the peduncle of the first 

 antenna. 



Curvature and dental formula of rostrum. — There is little 

 variation in the shape of the rostrum, but in the old males the 

 convexity of the dorsal border is much more pronounced than in 

 the females or young males. The tip does not turn up, the ros- 

 trum begins about halfway back on the carapace, and 1 or 2 

 teeth have their origin on the carapace. In all specimens the 

 distal teeth of the dorsal border are more widely separated 

 from one another than the teeth immediately posterior to them, 

 and in the old males the first 2 teeth on the carapace are slightly 

 more separated than those which immediately follow. The ridge 



