PYCNOGONIDA. 



EXPLANATION OF THE PLATES. 



Tab. I. 



Fig. i 4. Pycnogonum littorale Strom. 



Fig. i: First beginning of the embryo, from below. 



The proboscis and the three pairs of embryonal limbs are seen as low tubercles. 



2 : The embryo, somewhat more advanced, from below. 



The embryonal legs are seen as long appendages, all resembling each other, with the only 

 exception that the foremost pair show at the point an indistinct cleaving as the beginning 

 of the fingers of the chela or hand. 



3: Larva of the first stage, from below. 



4: Larva of the third stage, dorsal view. 



The embryonal limbs have all been thrown off, but the eyes are distinctly seen on the fore- 

 most, somewhat constricted part of the first segment of the trunk, and the three foremost 

 pairs of the ambulatory legs have all their complete number of joints. 



Fig. 5 6, Phoxichilidiiim femoratum Rathke. 



Fig. 5: Larva of the first stage, from below. 



The proboscis is not distinctly marked off, but seems to be a continuation of the trunk; 

 byssus-threads wanting. 

 6: The same, dorsal view. 



The outermost joints of the embryonal limbs have been cut off. 



Fig. 7 9. Pseudopallene spinipes Fabr. 



Fig. 7: Larva of the second stage inside the egg, lateral view. 



Very early stage of development. No trace of embryonal legs. 

 a. Chelifori ; b. foremost pair of ambulatory legs. 

 8: The same stage, lateral view. 



Somewhat more advanced; in this specimen the rudimentary embryonal legs are seen. 

 <7. First pair of embryonal legs; b. second pair of embryonal legs. 

 9: Free larva of the second stage, lateral view. 



Here (only in this specimen?) no trace of embryonal legs are seen. The byssus-threads are 

 now found. 



Fig. 10 15. Pseudopallene circularis Goods. 



Fig. 10: Free larva of the second stage, lateral view. 



a. First pair of embryonal legs; b. second pair of embryonal legs; c. the byssus-gland. 



The Ingolf-Expedition. III. 1. 9 



