26o THE COURTSHIP OF ANIMALS 



only light these regions display, that of phosphorescence, 

 which is generated by so large a number of those creatures 

 which are condemned by Fate to live this sunless life. 



" It is written," he remarks, " that the male must 

 exert himself to find a mate, and where sight cannot 

 help him in his search, a kind of blind-man's buff is the 

 only alternative. In this serious game many deep-sea 

 Crustacea, especially those of the Shrimp-tribes, trust 

 to the sense of smell, as the greatly developed outer, or 

 olfactory, branch of the first pair of antennae bears 

 witness. These antennae, again, seem to be used by 

 the males of some species for catching their partners, and 

 in Parapeneus rectacutus . . . they are turned into a 

 sort of crook for this purpose. This has long been thought 

 to be their function in the Prawns of the oceanic genus 

 SergestesJ^ In the male of certain other deep-sea Prawns, 

 the hind pair of foot-jaws are modified in a way which 

 can only mean that they are used for hooking on to a 

 partner of the opposite sex. In the deep-sea Hermit- 

 lobsters of the genus Munida the nippers are greatly 

 enlarged, as in many Shore-crabs, for the purpose of 

 subjugating rivals and embracing the females ; and in 

 all such cases these are much smaller in the female and 

 immature male. 



Mention of numerous cases has already been made 

 where the female is larger than the male, and is the more 

 pugnacious, and in such cases the females are generally 

 more numerous than the males. Some of the deep-sea 

 Prawns exhibit the same peculiarity. And in these the 

 sword-like forward prolongation of the head-shield is 

 far larger than in the male. Now this rostrum is the 

 most formidable weapon which the Prawn possesses, 

 so that we may, with tolerable certainty, conclude that 



