334 Geoffrey Smith 



freqiiently, to see a Sarign//i form with tlie antenna of the adult 

 male teleseoped up in the 4-jointed antenna of the youüger stage. 

 The separate species made by Sars and otbers for L. Sarignyi 

 therefore entirely break down, this form proving to be an imma- 

 ture male of dubia. The distinetion between the females dubia and 

 ueapolitana does not hold at all if a large series be examined. 



Turniug to the males Sars attempts to make distinctions on the 

 niimber of Joints in the antennae. Our 74 males in this respect 

 graduate into one another quite perfectly, and in respect of every 

 other character examined it was found quite impossible to split them 

 up into more thau one species. 



The total number of joints in the antennae of our males were 

 as follows: 



No. of joints 9 10 11 12 



Frequency 16 37 18 1 



and 2 specimens had 9 joints in one antenna and 10 in the other. 

 Now Sars' 3 kinds of male are separated as follows: 



L. Sarignyi (;f 9 joints in whole antenna 



L. dubia (j^ 12 joints 



L. Heapolitana (^f 8 joints. 



There is another point to be discussed. Fritz Miller in his 

 Für Darwin describes a very pronouuced form of dimori)hism among 

 the males of a species of Tanaid which he calls T. dubius (?) 

 (Kröyer). The figure which Müller gives leaves no doiibt that 

 he was dealing with our form L. dubia, or at any rate with a very 

 closely allied species. He states that the males of this form in 

 Brazil occur under two quite different forms, the one with highly 

 diöerentiated chelae and short sensory hairs on the antennae , the 

 other with femalelike chelae and antennae with long and numerous 

 sensory hairs. 



Since MüLLEK , no one has seen the second of these fornis. 

 Dohrn(9) suggested that a small male which he found in company 

 with L. dubia and fo which he could supply no female might be 

 this form. Imt this male has turned out to be Heterotauais anomalus 

 (Sars) to which I have discovered the female (see belowj. New 

 with regard to Fritz Müller's Statement it is true that the males 

 of L. duiiia exhibit a kind of dimorphism which we have described 

 in some detail (»n pp. IJIO and 324, and this dimorphism approaches 



