1 882.] Zoology. 145 



longer than the telson, broadly ovate, two-thirds as broad as long 

 and furnished at the tip with two short spines. 



Telson a little longer than wide, narrowing a little to the trun- 

 cated tip, which is provided at each postero-lateral angle with a 

 couple of stout spines. 



Female. — In the female the propodite of the anterior pair of feet 

 resembles closely that of the corresponding foot of the male. 

 The palmar margin of the second propodite is less oblique than 

 in the second foot of the male, and does not pass so gradually 

 into the posterior margin. It is also destitute of the jagged edge 

 and the square process of the male foot. There are fewer spines 

 along the margin. One of the spines at the posterior angle is 

 very long and stout. 



This species appears to resemble C. tenuis Smith, but is evi- 

 dently different. In that species, as described by Prof. S. I. Smith, 

 the first pair of feet are stouter than the second, and have the pal- 

 mar margin of the propodite much more oblique. The reverse 

 is true of the species I describe. Nor do I understand from the 

 description of C. tenuis that the posterior caudal stylets each 

 consist of a single segment. There are some minor differences. 

 From C. vitreus, judging from Prof. Cope's description in American 

 Naturalist, Vol. vi, p. 422, it must differ in the caudal stylets. 

 "Penultimate segment, with a stout limb with two equal styles," is 

 a statement that will not apply to my species, whichever the " pe- 

 nultimate " segment may be. 



Crangonyx tijurcus, n. sp. — General form and appearance those 

 of the Western variety of C. gracilis. Length of specimens about 

 9 ram . Eyes oval, black. Antennulae scarcely half the length 

 of the body. First two basal segments of the peduncle about 

 equal in length ; the first much the stouter ; the third segment 

 about two-thirds as long as the second. Primary flagellum about 

 twice the length of the peduncle, consisting of about twenty-four 

 segments. Secondary flagellum scarcely as long as the basal 

 segment of the primary flagellum, consisting of but two segments. 

 Antennae about one-half as long as the antennulae. Basal segments 

 short, the first provided with a prominent process, which appears 

 to be perforated (the opening of a gland ?). Ultimate and penulti- 

 mate segments of the peduncle elongated and equal in length. 

 Flagellum shorter than the two distal segments of the peduncle 

 and consisting of about eight segments. The antennae furnished 

 •with about a dozen curious sensory organs ; three of these on 

 each of the two distal segments of the peduncle ; the segments of 

 the flagellum with one each, except the terminal three or four, 

 which have none. These organs in alcoholic specimens resemble, 

 u nder the microscope, a lane o! it. 01 oblanceolate leaf having a 

 midrib and parallel veinlets running from this to the margins. 



Propodite of first thoracic foot subquadrate in outline ; a very 

 mtle longer than wide. Palmar surface somewhat oblique, armed 



