OBSERVATIONS ON LIVING SOLENOMYA. 275 



from the following description of them," etc. Drew 4 finds these 

 palp-appendages in Nucula delphinodonta functioning as food 

 collectors. The creature is immersed in mud out of sight and 

 only when placed in shallow mud was he able to observe its 

 behavior. The gills are certainly very small in Nucula. In 

 Solenomya, however, the gills are very bulky, filling nearly half 

 the mantle cavity, are highly ciliated and as we have seen the 

 palp-appendages rest directly on their anterior surfaces. There 

 can be no question that these appendages in Solenomya are 

 strictly homologous with the palp-appendages in Yoldia, Nucula 

 and allies. The gills, however, are the food accumulators from 

 which as we have seen the palp-appendages, collect the material 

 for nutrition. The mouth is difficult to make out in the living 

 creature. In two instances I have observed a slightly brownish 

 line marking the position of the mouth. 



While there are many features in common between Solenomya 

 and the other members of the order Nuculidse as seen in the 

 posterior position of the umbones, the primitive gills, the palp- 

 appendages, the fimbriated disk-like foot, the highly polished 

 periosteum; the absence of true palpi in Solenomya might be 

 considered an evidence that this peculiar form stands lowest in 

 the order Protobranchia. 



Some years ago Miss New r ell discovered at Annisquam a colony 

 of what was supposed to be Solenomya velum. A few w r ere 

 brought home alive, but circumstances were not favorable at 

 the time for detailed study and only a few r drawings were made. 

 The shell is apparently identical with that of S. velum herein 

 described, yet the character of the siphonal opening or rather 

 the appendages surrounding that aperture are widely different. 

 The single siphonal orifice is ano-branchial as in the other species 

 of Solenomya. Above this orifice is a very long unpaired tentacle 

 with broad base. On each side of the anal region is a broad flap 

 bearing five tentacles, the lowest one small, the next one long 

 slightly curved upward with three minor twigs springing from 

 its side, the next three smaller and diminishing in size. Below 

 this process is a wider flap supporting nine tentacles of nearly 

 uniform length. Between the anal and branchial processes 

 viewed from the side is a white band! I hesitate giving these 



