32 



interlocking along their anterior border, but not at all in contact along the 

 posterior, ending in an intricate but symmetrical bunch of hooks, teeth, and stiff 

 overlapping lobules. 



The thelycum consists of the following parts : — (1) between the 4th pair 

 of legs a broad, smooth, transverse, somewhat semicircular boss ; (2) between 

 the 5th pair of legs a pair of teeth or mammillar tubercles ; (3) in the interval 

 between the 4th and 5th legs a pair of pyramidal tubercles with often a small 

 sunken tubercle between them. 



The female rarely attains a length of 5 inches. 



The collection contains 37 specimens, registered as follows : — 



Ganjam coast, 45-50 fatlioms. j 



G. of Martaban, 67, 61, 46 fath. y " Investigator." 



Andamans, 55 fathoms. j 



,7 , T3, .,. . " Challencrer " (British 



Zebu, Fhilippines. "NT - T 



2. Paeapeneds investiCtATORIS, Ale. & And. Plate VI., fig. 17, lla-c. 



Piirapenejis ini'esd'jnforis, Alcock and Anderson, Ann. Mag. Nat. Hist. (7) III., 1899, p. 279: 111. Zool. In- 

 vestigator. Crnst. pi, xli. fig. 1, la, b : Alcock, Cat, Ind, Deep Sea Crust., 1901, p. 18. 



Distinguished from P. fissyrns by the following characters : — 



The I'ostrum in the female does not project much beyond the end of the 1st 

 joint of the antennular peduncle, and in the male does not far surpass the eyes : 

 it has a distinct dorsal convexity. The post-rostral carina fades away at the 

 posterior fourth of the carapace. The branchiostegal spine is as large as the 

 hepatic, and is placed some way behind and above the antero-inferior angle of 

 the carapace : this spine is not connected with any ridge, but a distinct groove 

 (= anterior part of cervical groove) runs in front of it and is then continued 

 backwards, beneath the hepatic spine, to define the anterior part of the bran- 

 chial region. 



The 6th abdominal somite is more than twice as long as the 5th and much 

 longer than the telson : the telson is shorter than the inner caudal swimmeret. 



The andricum is like that of P. ^fissiirus, but the terminal bunch of teeth 

 and petals is not so intricate. 



The thelycum is built on the same plan : it consists of a transverse semi- 

 circular plate between the 4th legs, supported by two lateral pillars which abut 

 on the 5th pair of legs ; between the pillars, posteriorly, is a median tubercle, 

 and the whole organ encloses a fossa which is shaped much like a figure of eight. 



