2o8 Memoirs of the Indian Museum. [Vol. V, 



Pachygrapsus propinquus (1-0075 — i 00975). Upogehia heterocheir (i-qoi — 1-0125). 

 Heleropanope indica (i-oi2 — 1-0265). Clibanarius padavensis (i-oio— 1-0265). 



Leipoden sordidulum (1-0125). Palaemon lamarrei (i 007 — I'oii). 



Urocaris indica (1-006 — 1-0265). 



Two species were found bearing eggs both in fresh water and in water as salt as 

 the Bay of Bengal in the vicinit)^ of the lake (sp. gr. i -000— i 0265) : — 

 Pcriclimenes demani. Alpheus crassimanus. 



Four species appear to breed only in water that is fresh or of low salinity: — 

 Ebalia malefactrix (i-ooo — i-oii). Caridina nilotica (i-ooo — 1-015). 

 Philyra alcocki (i-ooo— i-oii). Caridina propinqtta (i-ooo — 1015). 



As has already been remarked, Palaemon malcohnsoni and P. rudis breed exclu- 

 sively in fresh water and this is perhaps also true of Elamena cimex. 



In some species, such as Urocaris indica, Periclimenes demani and Alpheus cras- 

 simanus, there are perhaps two distinct breeding seasons, but our observations are 

 not sufficiently numerous for u^ to be certain that this is the case. The two species 

 of Caridina breed in the lake throughout the year, reproduction being, however, 

 inhibited when they are brought in contact with water of high salinity. 



Owing to the fact that Penaeids do not carry their eggs attached to the swim- 

 merets, as is the case with other Decapoda, it is more difficult to determine the 

 periods at which reproduction takes place. vSeveral circumstances, however, which 

 will be explained in detail hereafter, point to the conclusion that none of the species 

 of Penaeus or Penaeopsis breed in the lake. Prawns of these genera apparently enter 

 from the sea at the close of the post-larval stages and return thereto when they are 

 sexually mature. In the case of Penaeopsis dobsoni there is evidence which tends to 

 show that the females, having once bred, do not again re-enter the lake. 



The fifty-four species of Decapoda found in the Chilka Lake comprise thirty- 

 eight genera. The Paguridea of the lake have been determined by Dr. J. R. Hender- 

 son, Superintendent of the Madras Museum, who has published a short paper on the 

 subject in the Records of the Indian Museimi, describing as new, one species, 

 Clibanarius olivaceus. Of the remaining Decapoda thirteen species and one genus 

 do not appear to have been recos^nized before, while six other forms are recorded 

 for the first time from Indian waters. With three of the undescribed species I have 

 associated the names of Col. A. Alcock, Dr J. R. Henderson, and Dr. J. G. de Man, 

 to whom more than to any others we are indebted for our knowledge of the Decapod 

 fauna of India. The species of Callianassa is identified with a form hitherto known 

 only from a single claw found in a sub- fossil condition in vSiam. Athanas polymor- 

 phus, sp. nov., is of particular interest in the existence among the males of a 

 well-marked trimorphism. 



A complete set of all the species, including the types of those hitherto unknown ^ 

 is ])reserved in the collection of the Indian ]\Iuseum. 



