PHYLLOPOD CRUSTACEA 51 



Key to the Species and Subspecies of the Genus StrcptocepluiJus of the Indian Empire 



1. 5 with a complex frontal process, and strong spines on some of the 



abdominal segments 6". spinifer 



2. S with abdominal segments imarmed 



A. Main branch of finger of 2nd antenna of $ bifurcate distally 5". dichotomus 



B. Main branch of finger of 2nd antenna of <$ not branched 



i. Thumb l^yond thumb-notch at least as long as main branch of $ 



2nd antenna S". siniphw longiinanus 



ii. Thumb not over 4/5 as long as main branch of finger 



a. Basal joints of 2nd antennae of $ more or less fused dor- 



sally, obscuring frontal process 5". simplex arabicus 



b. Basal joints of 2nd antennae of $ not fused dorsally, frontal 



process visible from above 

 b,. Concave edge of sickle-shaped branch of finger sinooth or 



nearly so S. simplex simplex 



I);. Concave edge of sickle-shaped Ijranch spiniferous 5". simplex echinus 



Ecology and Zoogeography of the Indian Anostraca 



The Anostraca as a whole are slow swimmers with no sort of protective devices or 

 behavior. Introduced into an aquarium, they became immediate prey to any sort of fish, 

 and when they are in company with copepods or even cladocera, the Anostraca are always 

 the first to be eaten, usually being exterminated l^fore any appreciable inroads have been 

 made on the (ither forms. I once discovered the skeleton of a single, small fish in the dried 

 bed of a temporary pond of considerable size which was known to have contained Branchinecta 

 occidentalis the previous wet season. Outside of this one, rather circumstantial observation, 

 1 have never seen reported a single case of Anostraca and fish l^eing found in the same 

 waters. 



Possibly in connection with this vulnerability, various devices have arisen which have the 

 effect of preventing the co-occurrence of these phyllopods and fish. Arteniia will only live 

 in waters too saline for most fish to inhabit. The other forms may, in the main, be divided 

 into 2 classes : Those with eggs that require drying to hatch, and those with eggs requiring 

 freezing. In many temperate -regions the eggs may undergo both processes without detri- 

 ment. It is not known whether any species require both, or whether in any form drying 

 can substitute for freezing or vice versa. 



As a result it may be said that the Anostraca are ordinarily found in small, shallow 

 bodies of water, usually of a temporary nature, and that there is usually only 1 generation a 

 year. 



Of the Indian anostracans it may be surmised that both Branchinecta orientalis (the 

 specimens taken from Togarma Tso, 5,217 m., are from the greatest altitude I have been able 



''Found only in Ceylon and not discussed in this paper. Cf. Gurney. Spolia Ceylanica 4 (14-15) : 127, 1906. 



