tagtina egarine Laboratory !i 



STUDIES IN PYCNOGONIDA, I 



HARRY V. M. HALL 



In all our collecting but twenty-two pycnogonids were taken, 

 twenty of which belong to the same species and one of the others to a 

 different species of the same genus. The commonest had a spread of 

 legs of about three-fourths of an inch, while the other species was 

 about three times as large. The latter were so nearly the color of the 

 fucus on which they lived and so covered with debris that it is pos- 

 sible that they may be much more numerous than the number taken 

 would indicate. In working out this report I am indebted to Dr. 

 Leon J. Cole for many kind suggestions and much valuable assist- 

 ance. I have described the species found as follows : 



Anoplodactylus californicus n. sp. 



(Figure 4!)) 



Body rather short, lateral processes about as long as their own 

 diameter, radiate, with bases contiguous. First two intersegmental 

 lines barely visible. Proboscis cylindrical with rounded end, almost 

 as long as the length of the body. Diameter of the proboscis one- 

 half its length. Eyes not apparent, but a large conical eye tubercle 

 (bent to the right in the cut as is also the abdomen) arises from the 

 anterior edge of the body which projects over nearly the first half 

 of the proboscis. The abdomen is much the same shape as the last 

 joint of a man's middle finger and, like the eye tubercle is deeply and 

 closely pitted. The rest of the body is pitted but less deeply. Cheli- 

 fores large with well developed chela? and stout shaft, the whole 

 reaching about half their length in front of the proboscis. (In my 

 specimen the chelae are extended straight in front but there seems to 

 be no reason why they might not be bent in front of the proboscis.) 

 A few short spines on the chela 1 ; basal joints grown together and 

 apparently supporting the eye tubercle. Palpi and ovigerous legs 

 very rudimentary and wholly within the body (see plate for details). 

 The legs are rather long but stout, sparsely set with short spines. 

 First coxa shorter than its diameter, second coxa over twice the 

 length of the first and enlarged at its distal end, third coxa one and 

 one-half times the length of the first. Femur lunger than the com- 

 bined length of the cox*. Tibial joints each about three-fourths the 

 length of the femur. All joints of the legs stout. Tarsus about one- 

 half the length of tibial joints; claw two-thirds the length of tarsus 



