498 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM, 



The eggs iu the alcoholic specimens are about 1.8 by 1.4™"" in longer 

 and shorter diameter. 



In the following table similar measurements of this species and a 

 specimen of J>. Paycri are given for comparison. 



Measurements in millimeters and hundredths of length of carapax. 



B. gracilis. \ B. PayerL 



Station 



Sex 



Iien<rth from front to tip of telson. 



Lengtli of carapax 



Breadth of carapax 



Breadth of front 



Ix'ngth of eye-stalk and eye 



Greatest diameter of eye 



Lengtii of anti'nnal scale 



Breadth of antennal scale 



Length of sixth somite of pleon ... 

 Height of sixth somite of pleon ... 



Lenptli of tolson 



Length of inner lamella of uri»pod. 

 Breadth of inner lamella of uropod 

 Length of outer lamella of uropod. 

 Breadth of outer lamella of uropod 



2116 



Mm. 



39.0: 



8.4 

 5.5 

 1.4 

 2.0 

 1.3 

 8.5 

 2.8 

 6.1 

 2.3 

 7.5 

 5.6 

 1.8 

 7.0 

 2.4 



Per 



cent. 

 =464 I 



100 '. 

 65 



^li 

 15 I 



101 I 

 35 

 73 ! 

 27 

 89 I 

 67 I 

 21 

 83 

 29 



Per 



Mm. cent 

 50. 0^476 



10.5 

 6.7 

 1.6 

 2.0 

 1.0 

 9.6 

 4.3 

 8.0 

 3.6 

 9.0 

 7.3 

 2.4 

 8.8 

 3.5 



100 

 64 

 15 

 19 

 10 

 92 

 41 

 76 

 34 

 86 

 70 

 23 

 84 

 33 



Specimens examined. 



Bythocaris Payeri and the following species, B. nana, differ remark- 

 ably from Hippolyte and the allied genera in the reduced number of the 

 branchi;e and epipods. There are no epipods proper at the bases of any 

 of the gnathopods or perajopods, and no podobranchife nor arthrobran- 

 chige on any of the somites, as the following branchial formula shows: 



