86 Papers from the Department of Marine Biology. 



The basal joint of the first antenna is provided with 3 spines, the dorsal of 

 which is longer and stronger. 



On the merus of the third maxilliped there are internally 3 spines, the middle 

 one being the shortest; externally are 2 very blunt spines; the teeth on the 

 inner border of the ischiopodite are small and numerous. 



The chelae are missing in this specimen. The ambulatory limbs are rather 

 thickly beset with long coarse hairs ; spines on the merus not very well devel- 

 oped, but spines on the carpus very prominent. Dactylopoclite with strong 

 spine after end claw, others small. 



Colouration: Dark-blue pigment on carapace, with two fairly broad longi- 

 tudinal pigment-free bands. 



On Comanthus annulaturn were a few very small galatheids, white in 

 colour, with rather thin and membranous cuticle. Two which were 

 examined in detail were females with eggs and could not have moulted 

 very recently. In these the form of the rostrum conies very close to 

 G. inflata. It is short and broad, armed with 4 spines on each side, of 

 which the 3 anterior are prominent, almost as large as the median spine, 

 and the fourth is much smaller. They differ from G. inflata mainly in 

 the fact that the median spine is the same size as those which follow 

 instead of being distinctly larger. The rostrum is covered by coarse 

 hairs. The carapace is traversed by transverse grooves, but in one 

 specimen (the larger) these are broken up at the side into rounded 

 scales, while in the other the lines run interruptedly across. The cara- 

 pace is not pear-shaped, as in G. inflata. In another point the tw r o 

 individuals differ considerably, that is, the development of the third 

 maxilliped, which in the larger form possesses 2 spines on the inner side 

 of the merus and some very small blunt processes on the outer border. 

 In the smaller form (which was parasitised by a bopyrid) there is only 

 a single spine on the inside, while the outside is smooth. 



It seems possible that we are dealing with a variable species or 

 possibly a group of species which has the rostrum character described 

 above, while the carapace shape and to a certain extent its ornamenta- 

 tion varies with the size of the individual. The character of the third 

 maxilliped is also variable, the number of spines on the merus increasing 

 with age. 



With regard to the strong development of pigment in one and its 

 non-appearance in others, in spite of the fact that all were found on 

 crinoids, I can make no suggestion of any importance. It may be that 

 in a variable species some individuals are incapable of an assumption 

 of pigment. It is not to be supposed, I think, that these unpigmented 

 individuals had but recently taken up their residence in the crinoids, 

 for they were mature females with eggs. However, I can not pretend 

 to explain, on the strength of only three specimens collected, a phenom- 

 enon which is of so much biological interest. 



For the present, then, I wish to recognize an "inflata" group, distin- 

 guished by the short, broad rostrum with 3 or 4 spines on each side (of 



